Hello all. I have a 99 integra 2dr and i want to do an exhaust setup for my stock car. I decided on the Spoon n1 so I recently ordered 1 from http://www.randdmotorsports.com . I also just ordered the carsound cat 2.5inch and the b-pipe 2.5inch from kteller. But i just realized that the spoon n1 axleback is only 63mm (2.38 inch i believe diameter). So my question is...going from a 2.5inch headers to b-pipe and downgrade to 2.38inch axleback is that gonna cost me my performance? isn't thats the samething as bottlenecked?

Should i just cancel the 2.5inch b-pipe from kteller and get a b-pipe with 2.38inch? IF so which b-pipe should i get? Does that mean i have to change my headers collector size too? IF so which should i get? does muffler shop do 2.38inch custom piping?
thanks guys in advance. sorrie for so many question but... hope to get answers soon so i have time to cancel my orders if i have to.