As with most things, there are pluses and minuses on each side.
For spacers, cheaper price is the biggest advantage.
Here is an odd advantage to spacers that I bet no one else will mention. (Or perhaps even agree with!): For me, it seemed there was a subtle perception advantage with respect to warranty by going the spacer, body lift, motor mount lift route. I went in and spoke to service manager before I even bought the Jeep and said: “I plan on a sticking a few spacers here and there to provide some additional clearance and allow me to put slightly bigger tires on. I’m not going to be creating some ‘Monster Jeep’ and, in fact I won’t be replacing a single factory part. Will I have any warranty issues with that?” It made it real easy for the guy to say, in front of witnesses: “No, that won’t be a problem.”
For springs, perhaps the biggest advantages are that you can actually improve the ride and flex of your Jeep. Particularly with Old Man Emu (OME) springs and shocks. It is reported that the OME springs may only net about 1.5 inches on the Rubicon so many are using them in conjunction with small spacers. Based on what I have read and my son’s experience with OME on his XJ, they are really sweet and highly recommended if you aren’t going higher than 2 inches anyway.
With other brands of springs you can choose to go higher than 2 inches if you wish.
Well, that certainly doesn’t exhaust the subject, but there are a few comments. . .
i agree that you should not have any warranty issues with a coil spacer set up. they are really only 1.5" to 1.75" in lift. they are good in that everything is still factory. they will work okay with your stock shocks too, i think the better kits come with bump stop extensions, (mine is the teraflex kit and it came with the extensions front and back).
the rubicon does come from the factory with stiffer springs than the sport or sahara, so most springs you buy for a 2" lift do not net you as much lift as they do on the other model TJ's.
IMHO, the coil spacers are a good choice to help give your jeep a little more clearence underneath.
In my opinion, and the reason I chose springs, is that coil spacers only give you extra clearance--and in some cases can hinder ride quality by compressing the springs too much--whereas springs give added clearance, added travel (flex) and, depending on the spring, improved ride quality.
Ok, now another question. My Rubicon has an automatic. With a two inch lift will I get a vibration and need to use transfer drop kit? With a spacer lift Will the stock shocks hender the flex much? I understand that the shocks add a bit to the overall height. If I add a 1.75 spacer and new shocks won't the overall lift be about 1.25?
i have an auto too, i'm running the teraflex 1.75" coil spacers, net gain over stock height was 1.75". i still have the stock shocks, and they do limit the amount of flex you get, but you've got lockers front and back.
the front skid limits the amount of flex travel you'll be able to get too, as the front drive shaft will hit it.
i will be putting a set of 3" teraflex springs later on, i only want enough lift to run 33" tires, a body lift of 1 to 1.25 inches, so i can get the skids up higher.
I thought I might have had just a little vibration "on launch" (0-2 mph) after adding my 1.75" spacer lift and it seemed to go away when I added the 1" MML, but it could have all been my imagination. Theoretically, you should not have a vibration issue with a 1.75 inch spacer lift.
Okay, I haven't done it yet so all of my spouting off is just theory. But, I'm doing the OME this w/e and I've asked the guys at ARB a lot of questions. One guy told me that a 2-2.5" lift that the new OME springs give shouldn't cause a problem with vibes on a manual. I don't know about the auto. Another guy at ARB told me that a 1" motor mount lift should correct the geometry if I was still worried about it. I wouldn't go with the t-case drop down just because it seems like we've already lost a bit of t-case clearance with the Rubis anyway. So, later when I run the 33s I'll do the 1" MML and 1" BL on top of my OME springs and that should do it.
By the way, Ron (PBR) should be able to give some more practical advice since, unlike me, he's actually done it already.
The factory shocks limit flex at factory height. If you put in any type of lift, you will still get the same flex, so all you really did was change your ride height. It may get you over some obstacles, but if you need the it to flex up as you do it, then you are out of luck. So really no matter what you do you will need longer shocks to gain more flex. If you remove the factory shocks you will lose about 1/2" of height on your Rubi. This is due to the factory shocks being high pressure nitrogen (approx. 90lbs compression force).
Spring spacers are fine, as long as you go with a quality kit that includes bump stop extensions like Griz stated. The reason for this is that you don't want to compress the coils on the spring all the way together. This could cause what is called SET. The coil may not return to its original height. I have heard some manufacturers state that they have already done this, but if you can avoid it then avoid it just to be on the safe side. One note of caution on the spring spacer since I had a teraflex spacer on mine and the spring pressed against it. The Teraflex spacer deformed and caused a real strange ride especially off road. If you are going to use a spacer either place the factory spacer between it and the spring, or use one that is solid.
Spring lift may or may not give you the stated height. The OME kit (Heavy duty) was once stated as being 2.5", but on the Rubi's and in the new cataloge, the front springs will only give 1.5" of lift, while the rears seem to give right around 2-2 1/4" of lift. You can compensate for this with an additional factory spacer (they have a steel insert to handle the pressure of the spring) in the front to even it out.
With either lift you are changing you ride characteristics. You will be changing out the shocks on both, and the addition of the springs on the other. I have run OME shocks with both OME springs and RE springs and have spent many hours riding in a Teraflex springs spacer with OME shocks 2002 TJ. The ride was good in all of them. The ome spring/ shock combo ran the best, with the RE and spacer being about even. Remember the RE is 1.5" taller.
The biggest advantage I see is that the spacer lift is much cheaper for inches gained. You don't change out any factory parts with the exception of the shocks for more travel. It is a good way to start.
As far as your auto haveing vibes every Jeep is different. I did an OME install on a friends Auto and it has no vibes, no MML either. It does sit nose high in anticipation of the winch and Bulletproof bumper install, so time will tell. The impact on your auto skid has already been stated, but that fix just involves a little cutting, BFH and a reweld to make a ramp under the driveshaft, or you could put on a skidrow or Warn skid plate.
I wouldn't do a T-case drop, since you would lose 1 inch of what you gained, kind of unproductive.
All of your input has been very helpfull. One thing I really like about this forum is that there is no bashing or bad mouthing each other. Everyone respects the opthers opinion.
I think I have settled on the OME Spring lift. Any suggestions on a retailer or who has a good price?
Thanks again for all of your help.
By the way. How many of you end up in Moab every year? I grew up there and spent my childhood 4 wheeling in a CJ7. My dad was one of the originating members of the Red Rocks 4 Wheelers. Most of my Family is still in Moab so it's an inexpensive vacation for me.