bro normally in B5 (tukar nama) they dont check for the exhaust loudness...so far la no problem lepas...
if use runner or used car(also use runner services) should be no problems at all...but if you doing ur self, and the puspakom guys wanna tekan u, i think its possible....
i previously did B5 on my own twice, both cars had very loud exhaust, the puspakom guys can rev the engine loud loud somore... still pass... so i think don worry so much bro.
just becareful of ur tint. this is very common to kena fail, kopek(torn off) or ask you to remove and come back.
just my 0.01 cents experience :)