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[Chadillac2000]

Alright so the downpipe and hi flo cat or test pipe won my next mod of choice, so heres my dilemma, i have a hks super drager catback which i think has 3 inch piping, almost positive, so what would i need to get to match up with this and what would i get the most success out of?

 

[Chadillac2000]

and what does the o2 elimator do to help? or should i even get this

 

[DSMSpyder99]

if ur not going to go bigger than a T-28 then you will be more than fine with a 2.5 Downpipe and 2.5 cat/race pipe. If the HKS dragger flanges down to connect to the cat (im pretty sure it does cause you said you only have a cat-back so its gotta bolt on to the stock cat) then a 2.5 Downpipe w/ hi-flow cat then it goes to a 3 cat back is a complete bolt-on i should know cause that what i have