Showing 3 products
Racingline Performance Air Filter S4/S5 B9
APR ECU Software S4/S5 B9
QST ECU/TCU Software Audi S4 / S5 B9 / SQ5
QST have been offering performance ECU software since the early 2000's, developing and offering some of the industries leading ECU and TCU software to our customers. Developed and verified on our in-house MAHA dyno, then verified in the real world with performance timing equipment, we offer a full range of tuning requirements ranging from Stage 1 all the way to Stage 3 with bespoke hardware changed to unlock efficiency.