how much tuning would be needed if any with the addition of a hi flow cat replacing the stock cat...current mods are dp, cb, intake, ic, efi pms

 

anyone??

 

It's your boost level that's really the concern.

Howevery, you won't know for sure unless you stick it on a wideband O2 and see your A/F. Maybe none, maybe some.

You can't really guess at A/F ratios. If it's a concern, stick it on a dyno with a wideband. Otherwise, just put on the high-flo and don't worry about it.