I just go my HKS 30th anniversery 3" exhaust system today and I took it out of the box, guess what. the end that attaches to the catalytic converter is flanged down to 2.5" what a disapointment. I already got my 3" downpipe and 3" cat delete pipe in the car. I was hoping that I would have 3" all the way from the turbo to the tip but now I have this 2.5" area for about 1.5 inches in the middle. do you think this will affect power much. I could cut the HKS system and weld in a new 3" piece, do you think it would be worth it? I would hate to cut into the polished HKS system though.

 

i dont think it will make a drastic difference. i have the same exhaust attached to UR pipe...im happy.

 

its not a big deal, thats what i did, i had road race cut the 2.5 tip off and weld on a 3 incher. Ill take some pics soon, but the install was CLEAN. You can even see where it was welded on, other than the fact that the color of the metal is different

 

its under the car... its gonna lose its shine soon anyway... just weld in a 3"

 

i have a higher power hks catback sitting right next to me...... and mine does not taper down to 2.5 at the cat

though its for a 02' WRX if that matters...