I began to attend autocross events and felt a more robust braking setup was called for.
The stock setup on the car could be enhanced at significantly less cost than the Stoptech kit would cost. Various options were available but my concern centered on how well a mix and match setup would operate, especially given how critical braking is to automobile safety. There seemed to be mixed results with the mix and match setups I had read about.
- STOPTECH: Widely used on the S4 and reasonably priced when compared to other brake upgrade kits of this caliber.
- BREMBO, ALCON, STASIS: Used to varying degrees by other S4 owners from what I could tell. All seemed to have a good reputation going for them. I had the impression they were more expensive than Stoptech for a comparable setup.
- MIX AND MATCH: Some people were happy but others had experienced problems when putting their own upgrade together. By far the least expensive option as well as leaving room to choose components I wanted.
Stoptech. I was on the fence about the upgrade until Stratmosphere had a demo set available for a good bit less than they regularly are sold for. I was also more comfortable going with a kit that had wide use and almost no negative comments from people who had the kit.
I had the Stoptech 332 big brake upgrade done on conjunction with 17″ SSR Competition wheels. The calipers do fit under the wheels with room for the wheel balance weights. One thing I did notice right away was that the wire from the Porsche brake pad wear sensor stuck up high enough above the caliper to rub the inside of the wheel. To resolve this problem I used a zip tie to pull the wire down closer to the caliper.
Under normal driving conditions I have not noticed a significant change with these brakes going from stock. The stainless steel brake lines do provide more resistance earlier than the stock lines did. Under hard braking the new calipers can more easily bring the ABS system into play.
Of course the tires play a significant role, and the all-season Pilot Sports I have on the car presently are not the best to generate short stopping distances. I have not had the opportunity to take the car to a track where the improved fade resistance of the larger calipers would come into play.
Bottom line, for a daily driver these brake upgrades are unnecessary in my opinion. Stainless steel brake lines may well improve the feel enough to make happy somebody who feels that the S4 brakes are mushy.
Given the key role that tires play, somebody looking for shorter stopping distances would do well to get better tires first. Finally, my first autocross event began with a braking exercise that subjected the stock calipers to roughly ten 60-0 runs which left them smoking, but still hanging in there. Those runs included short cool-down periods in between while other drivers went.
The reason I upgraded the calipers was for the times I would be taking the car onto a track where there would not be sufficient time for the stock calipers/rotors to cool down. I have not had the opportunity to subject the Stoptechs to that type of driving yet.
Finally, they do look better than stock.
I’ve had no complaints about the Stoptech BBK. It has not caused me any problems and they have worked well. I don’t think I have yet to push these brakes beyond what stock brakes could handle, and that includes an Audi driver’s event and track day. I have not reached the point where my own driving pushes the car to a point where upgraded brakes are necessary.The pictures below show the condition of the calipers after two years of useage. The car was just washed, which is why the rotors look the way they do.