I have the sport exhaust with Milltek Secondary Bypass and I would say there is a huge difference. There are more pops and bangs but you notice it the most when you open up the throttle and the car up shifts, the crack is insane! Definitely worth the £170!
I am currently in the process of discussing a possible group buy with Wagner on the EVO3 intercooler.
As of yet no prices have been indicated but they have requested an approximate number of people interested.
If you would be interested in the Wagner IC and being part of this...