Well i have now had both the TT Mk 2 lower control arms/S3Cupra Hub combo and TT Mk2 lower control arms/TT Mk 2 Hubs combo fitted to my car and here are my thoughts on both.
Combo 1: The TT Mk 2 lower control arms with adjustable camber at the ball joint combined with the S3-Cupra hubs gives a bit more than -2 degrees negative camber at the bottom of the strut along with lower weight which combined with the hubs lower weight is a plus.
Things to consider is the lower ball joint has to sit differently that designed for (Which for me has had no negative effects or troubles whatsoever) Also by using this hub you are reducing the chioces in BBK kits as the hub is 16mm wider where the bolts for the caliper carrier sit in the hub.
Combo 2: The TT Mk2 lower control arms combined with the TT Mk 2 hubs gives about the same weightreduction as combo #1, the negative camber achievable is lower than with combo #1 app. -1,8. With the amount of camber the track width is extended by app. 22mm in each side making the rim/tyre options limited unless you have the option of fitting adjustable upper strut mounts. You will also gain better steering geometry as the lower ball joints sits lower along with the steering point reducing the risk of bump steer (I assume
)
Things to consider is that the lower ball joint sits as intended and you will now have the same amount of BBK options as the steel GTI hubs allows. to get the TT Mk 2 hubs fitted you need to either cut 5mm off you steering rack in each side or ideally get a TT Mk2 steering rack, along with TT Mk2 steering rods and bearings. Also you will ideally need some TT Mk2 drive shaft as they are 15mm longer than the ones your car has.
All in all i would say you really need to consider the cost in choosing the TT Mk 2 hubs as the expenses is great compared to the gain in steering (feel?)
Just my thoughts, me personally have enjoyed the quest and feel that the gain is there, but should i think twice i would not chose combo 2 as the expences is high and it's sort of a road with a point of no return.
I hope you can use my opinions in your quest after mods to do