Well i jsut got heamans long tube headers in 2day, and two moroso spiral flow mufflers. this march 22nd, it is getting the whole exhaust done, true dual 2.5inch, temporary dual cats. is this enough breathing room? as for the motor, im going to stop upgrading it till about 400 hp, will this exhaust sit well with it?

 

Dual 2.5" exhaust will have no problem handling 400HP.