Is there a big difference on the peak torque made by T34.48 and T34.55, given that same engine and boost level is used? Bigger exh. housing will surely give noticeable bump in bhp and smaller exh. housing will give more torque (and hp) in lower revs but is it really worthwhile to go .55 instead of .48 if (midrange) torque is importance?

I wouldn't want to chase numbers and peak hp, so that's why I'm looking for these smaller T34's. Is there any price difference beetween T34.48 and T34.55?