I'm trying to decide what to do with the Aprilia v-twin engine... fabricate a full airbox, or just go for a backing plate and small sausage style filter.

Can anyone explain in general terms how they would differ performance-wise?

Ta!

Airbox every time for me - preferably with a cold air feed , if it's power you want (otherwise , warm air may hurt the power a little , but does help economy)

for noise supression and low down torque stick with the stock air box ,i gained a few hp peak with the sausage filters ,induction noise is a big issue with v twins 11db difference between stock airbox and open foam filters on a tl1000

Cheers guys!