I'm looking for a bit of advice here, what do you think...

So im running a B18C Type R with a Mugen air box, ITR T/B, skunk2 inlet, spec 3 Buddyclub cams, PLM RMF Manifold which is 2.5" at flange and then a 70mm Skunk2 Catback

I have a brand new skunk2 pro series 68mm T/B lying around and im thinking of putting it on but half paranoid I could lose power? What ya think?

After a map could i potentially regret it do you think?

 

Its hard to say, only a dyno will tell you if gain/loose any. But imo you prob would not loose hp but may not gain hp either.

 

As long as you portmatch the TB to the manifold, you should see a small gain in the upper RPM range.