my buddy has a b5 s4 all rs4'd out..rs4 y pipe..k04s..blah blah (i dont know exact details..im a vw guy).

he spikes 1.2 bar and it slowly tapers downward as he approaches redline. i know the car should be and feel much faster. can he crank up the boost safely and how much?

(for the record does anyone know what the capable HP numbers are of an rs4 tb/k04(s)/y pipe/etc setup costs?

is he using the right gas for his tuning? maybe the ECU's pulling timing back.