Thinking about mounting my Spoon N1 axleback which is just lying in the garage.

The other mods on my dc2 is a mugen intake, mugen header and a T1R high flow cat.

Can i expect any performance gains, or is it mostly the sound that changes?

Guess i'm better off with buying a cat-back exhaust?

Some guy offered me a Tanabe Ultra Medallion cat-back.

Is the cat-back worth the extra money?

 

i thought T1R only made resonated test pipes

you would see a few more ponies with a full catback, but it will be marginal at best. the oem itr exhaust has a bottleneck in the b-pipe.

 

Switching to a highflow cat or a test pipe will produce performance gains.
Adding your header will also..

Look into a set of cam gears & engine computer tuning too.