Does anyone know how well this backbox compares flow-wise to the standard Sti backbox?
I knocked out the the reducer (located just inside the flange joint) and fitted it but haven't noticed any difference in perfomance like I did with previous backboxes.
Any ideas?

 

not sure about air flow mate,but the Genome is an awsome backbox. i have one on mine which you could buy for £6500 with a free car