Are you saying the combination won't work because the Cayenne caliper will hit the TT ball joints? Only reason I'm asking because I know that Superpro/Passat LCA + Superpro RCA + Stoptech 328x30 won't work because the rotor hits at full lock, but if you run the stock GTI LCA or stock ball joint it will clear just fine.
The spacer won't work because, if I'm understanding your statement, the clearance issue is between the BBK and the ball joint, not the BBK and the wheel spokes.
There is some misunderstanding on what I'm asking. I'll try to clarify more about what I'm asking. My Clarification is going to be a long winded one so bear with me. Please note that I have not purchased and on the alluminum spindles and what I am explaining is pure from research and discussions. If I am completely off base please correct me as this may benefit the community. Also please not that I use inboard and outboard a lot due to my boating roots.
Yes it'll be possible that the rotor used with the cayenne calipers may hit the ball joint at full lock when using the GTI steel spindles. not sure this will be the case with passat or TT spindles. What I was talking about is different. We all know that the Cayenne has the same bolt pattern for its calipers as the GTI. However in order to mount the Cayenne caliper to the GTI's steel spindles you need to position the calipers mounting face inbetween the rotor and the spinlde's caliper mounting face (I call this the outboard or road facing mounting face), where the GTI's stock caliper/carrier is mounted on the inboard / wheel well / Chassis facing side of the steel spindle's calipering mounting face.
When you start to look at the Passat and TT Spindle caliper mounting flange, you'll notice it is thicker than the GTI's steel spindle. How much thicker I am not sure but I know there are measurements somewhere in another thread on this forum. Now orient your imagination so you are starring directly at the side of the caliper mounting flange so that the outboard / road facing side is to the Left (+X direction) and the inboard / chassis facing side is to the right (-X direction). Draw a vetical section line straight down the middle of this flange along the part that actually connects to the spindle. Do the same for the GTI's steel spindle and place it above the aluminum spindle so that they don't overlap.
Now that we have our comparison diagram setup in our minds lets start to analyze it. So I talked about that the aluminum spindles Caliper mounting flange is thicker than the steel spindle and I mentioned that the cayenne caliper mounts on the outboard / road facing side. Now that we remembered those two points, if you call back our comparison diagram from the dark reaches of your mind you'll see that the inboard side of the aluminum spinlde's caliper mounting flange stick just as far our in the +X direction as the GTI's steel spindle. Hence the reason why we can use Stock GTI brakes (caliper and caliper carrier) with passat spindles and only need a longer bolt. But if you turn your attention to the outboard side of this mounting face you'll notice that the aluminum spindles face sticks out farther in the -X direction than the steel spindle. This is probably due to Aluminum being a weaker/softer material and the wanted to beef up this mounting face that takes a lot of load while braking. Again I am not sure of the exact distance this outboard face sticks. I would need to recall those old threads to determine the exact difference in thickness, but I think its a few mm's. But this causes the caliper's mounting point to be closer to the rotor. It wil alse cause you to not be able to slide a nut in betwen the rotor and the caliper to fasten the caliper to the spindle even if you use a longer bolt.
Now that we have finished our comparison of the differences between mounting faces of the two spindles I'll reask my question.
Would it be possible, given I knew the exact differences in thickness that the TT or Passat caliper mounting face sticks outboard toward the road, to take a wheel spacer (of the exact or great than thickness difference) and place it between the wheel hub / bearing and the rotor to push the rotor out farther thus allowing me to fasten the Cayenne caliper to the Passat or TT spindle? This problem could be solved with a custom rotor hat and a two piece rotor but I don't have time or the expertise to design one. I will state that I'm running Xola3que's custom two piece rotors that he was selling on this forum. I could also solve the problem by machining the Passat's or TT's outboard face down to match the same dimensions as the GTI's steel caliper mounting face. The problem with machining the face is will the mouinting point break when I slam on the brakes in an emergency condition? That is a risk I'm not willing to take. Another concern I forsee people asking is, the rotor is supported by the ring around the axel bolt on the wheel hub. By pushing the rotor out further it has less support on that ring. Well to answer that concern, I currently got rid of my lug bolts in favor of wheel studs and Lug nuts. So the rotor will be supported by the wheel studs. There may be some rocking of the rotor as it might not fit snuggly on the studs but I plan on finding a longer bolt that fastens the rotor to the wheel hub. May have to dill a hole through the spacer for the bolt to pass through.
So does anyone think this is possible?
The TT parts can be challenging to fit in unmodified fender arches, since they push the track width out. Fortunately, I'm covered there with aftermarket fenders on the A3. But of course you're right: Camber is not really adjustable beyond min/max.
Keeping the rubberized top mounts was another reason why I opted for the OEM parts for DD manners. If you check car-parts.com, you can often find used parts. My TT spindles are on the way for $375 incl. shipping.
JRutter, Let us know what tie rod you go with. Supposedly Tyrol Sport have found an OEM tie rod from another VW/Audi vehicle that will me the requirments to use the TT spindles but they're charging $250 for them. If you find out what they maybe using please let us know.
Yea I had to roll my fenders when I put the TT LCAs on. If I got the TT Spindle route as well I would need the aftermarket wider fron fenders for my car.