After 5 track days one of the rear caster bushings has failed pretty badly. I can not recommend that these be installed on any car that will see track time. They were great when new but these are not worth the effort.
One of the things I've missed from my mk1 was the immediate turn-in response and a more go-cart like feeling. The RS makes tremendous mechanical grip but at anything below ludicrous speeds it can feel a bit lazy, even in sport mode.
My mk1 was modded to improve turn-in with a set of original pre-recall front control arms with poly bushings and the H&R coilovers with a fairly stiff rear spring setup certainly helped as well. I never replaced the swaybars. I attribute the slightly lazy feel of the RS to the slower steering rack, longer wheelbase and softer spring setup.
I've tried to address part of these issues with the Superpro kit (SPF3273K and SPF3346K) and of course MSS helps as well. It's a bit difficult to separate out the improvements in handling between the Superpro bushings and MSS since I installed both at the same time but there are certainly some things that are clearly from the bushings so I'll try to keep my comments here to just those traits.
So what are these things anyway? The front control arms in the mk2 have a small bushing up front and a larger in the back that is mounted in an aluminum bracket. The larger rear bushing is oriented the same as the front which is an improvement over the mk1 since the arm is pivoting freely and the bushing doesn't bind up.
These are both fairly dense rubber but the rear bushing especially is a larger diameter so there is some room for improvement in hardness to improve steering response. Additionally the Superpro kit has the rear bushing setup offset so that it can be positioned in different orientations. For my install I chose to orient it to maximize caster. There are a couple of benefits of this; you get improved straight line stability, increased steering weight off center, and additional camber as the wheel is turned. This last bit is cool because in theory you can run less static camber but still get more camber through a corner.
The install did not turn out to be trivial at all. I've posted some info here so that folks that undertake this or have a shop do the work will know where some of the gotchas are ahead of time. It's not a typical DIY install tho.
The arms themselves are relatively easy to remove. Four bolts each side attach the arm to the subframe and then the three nuts that connect the arm to the balljoint. Several of the subframe bolts were seriously overtorqued on my car so needed a BFW to remove. There's also a bit of an issue with getting the forward bolt out of the passenger arm. This one backs out straight into the oil pan. There are two options to deal with this; drop the subframe or raise the engine. With the two dogbone bolts removed I figured I'd see if I could move the engine up just enough to slide the bolt out and it worked. This is NOT the factory approved way to do it but it worked for me.
Once the arms are out you need to have someone press the old bushings out and press the new bushings in. We went to two machine shops and the first didn't have a press with sufficient clearance and the second had a really nice press but the owner did not want to risk working with an aluminum arm because they had issues in the past (believe he said they cracked one). Luckily my suspension expert, Russ Scott who has a mk1 TT and his own press, was with me and the shop owner was willing to let us attempt the work on the press! This was really fortunate because we would have been SOL otherwise. I believe that if you get new arms at the dealer they come with the bushings pre-installed so no guarantee that a dealer would even do this work. There is an option to buy complete new arms direct from Superpro with the bushings already fitted which is what must VW guys do since they have stamped steel arms. This is quite a bit more expensive than just buying the bushings but you might be able to offset that cost since the mk6/mk6 VW guys consider mk2 TT arms an upgrade.
Anyway, Russ was able to work his magic and after a few hours of fiddling with the press and assorted tools we got the bushings pressed in and were back on track. Here you can see the bushings installed. This first one is the passenger side and you'll note the offset compared to the centered stock orientation. The second pic is of the front bushing. Please excuse all of the Energy Suspension lube :)
Reinstall all of the bolts with new OEM and torque to factory specs. Due to the offset of the bushings these will crank in a lot of toe out so you'll want to get it realigned.
Driving Impressions
Post alignment the car has gained an additional 0.5^ of caster. I don't really sense any increased NVH with these installed. There might be a bit more rumble on rough surfaces but it's minor. The additional straight line stability can be felt as soon as you get over 30mph. Below that speed the steering is so overboosted that there's not much difference. Above 30 the car feels locked on straight ahead. Start to turn the wheel and the front end responds quicker (note, some of that is also due to MSS kit install) and there's additional weight felt through the wheel too. It's not so heavy that you can't still steer with your wrists, it just feels like the car is pushing back a bit which I like. There's also a noticeably faster return to center as you unwind lock. Rapid transitions are darty and the steering feels much more alive. I'm really pleased with how this turned out. Coupled with the MSS kit the RS now feels as nimble as the mk1 did. I'm very excited to get it back on track in April!
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