The B7 marked a significant change in the A4 lineup to date, introducing the new "shield" grille and FSI technology. The new direct injection allowed for better output and efficiency but also requires maintenance of fuel pump follower inspection every 10k miles and carbon cleaning every 60k miles. Tuning to Stage 2+ (Tune, HFC, HPFP) offers a nice jump in performance while still offering daily driveability.