How obvious was your clutch slip when cold? Any videos?
I've done some research on the clutch options, and there isn't a clear best option. Some options are:
1) Stock. Many folks report success running the stock clutch on stage 2 (and even stage 3) TT-RS cars if you don't do aggressive launches. There are no reported holding torques published, so it's hard to compare when you get with the "upgrade" clutches over stock. One thing that is great about the stock clutch is that it has a self-adjusting mechanism built into the pressure plate that adjusts for disc wear to keep the preload / engagement consistent. I've yet to see an aftermarket clutch that includes this, which can result in issues down the line as you wear down the disc.
2) Sachs "performance" pressure plate + organic disc. This is rated for "550+ N*m", which is equivalent to 406 ft*lbs. That's barely over the stock torque of ~360 ft*lbs, and well below even a Stage 1 reflash. So again, it's not clear what this clutch buys you over stock, since stock is also organic. Note that most all of the aftermarket clutch options use this Sachs "performance" pressure plate and repaint / rebrand it, with different disc materials. This retains use of the stock dual-mass flywheel.
http://www.sachsperformance.com/Sac...-quattro-250-kW-;-05/2009-:::2_3_538_539.html
3) Sachs "4-puck" racing clutch disc. This is what APR recommends (it supposedly holds 600+ ft*lbs). But due to the reduced friction area, this clutch will not last anywhere near the length of a stock clutch (far less total material that will wear more quickly over time). This retains use of the stock dual-mass flywheel.
4) DXD / South Bend clutch kits. From what I can tell, DXD / South Bend takes the Sachs "performance" pressure plate, paints it red, and then takes OEM discs and removes the center spline section (to re-use) and attaches their own friction materials (depending on the "stage"). I've heard that they have versions that retain the dual-mass flywheel, but most installs seem to go with a single-mass flywheel replacement. The latter has various NVH and engagement smoothness impacts (nothing I wanted to compromise for a daily driver).
5) Dual-disc clutch from 034 Motorsports (Clutchmasters unit currently). 034 is testing their own custom clutch solutions for the TT-RS. I'll let them chime in on any issues with their setup, but IMO this is an "aggressive" racing solution, not a daily driver (it requires changing to a single-mass flywheel).
6) Dual-disc clutch from Helix (UK). They currently make a "race" version that is 215mm in diameter and requires a flywheel change to single-mass, and is unsprung. A few folks in the UK are running these (including "johnnyc"). The "puck" version holds 870 N*m (641 ft*lbf), while their organic face version holds 700 N*m (516 ft*lbf). They are supposedly working on a "street" version in a larger 228mm disc that allows them to fit springs in the twin plate config for smooth engagement for road cars. I suspect though that hanging all of this inertia off of the transmission will be a problem for the synchros, which were designed for a light unspring disc (and a sprung dual-mass flywheel instead).
7) Dual-disc clutch from APR (still in development with no clear timeframe). This is supposedly a carbon/carbon clutch disc setup, with serviceable carbon friction surface inserts. Hard to tell much else until more info is released, but if it's anything like the Stage 3, it will be a long time in the making (and of course worth the wait for those that do).
So after all of that, I'm tempted to just stick with stock (or replace stock with stock if I have slipping issues), because:
1) stock is designed to work with the dual-mass flywheel
2) the stock pressure plate auto-adjusts for even loading / release control as the disc thickness changes over life as it wears
Last thing I want to do is put in an aftermarket clutch, have it work fine today, and then start slipping / develop issues as it wears (plenty of horror stories of those online).
Any other folks have solutions they can share?