If I was to replace the stock exhaust and intake air filter with aftermarket TBE, dp, tp/hfc, and drop-in filter and get a tune...when and why will the stock BOV be needing to be upgraded? Need your reasons and help with BOV with above mods please.

 

why - because the stock one leaks. if you have an evo8 that is.

when - as soon as you buy the car.

 

Since you have an 03, its worthwhile to upgrade even if your stock considering your plastic diverter valve leaks boost. Your best bet is the JDM MR diverter valve like the ones found on the IX.

 

my first mod was a boost guage, followed several days later by the JDM valve. It holds boost better with less taper at the top. Must have for Evo 8.

 

if im not mistaken though even the ones on our IX's will start to leak once you exceed 25 psi. so if you plan on pushing more than that then i would upgrade to an even better one than the JDM BOV found on the IX

 

go with the forge rs really nice..

 

Yeah, but how many people push over 25psi? On the IX, that's a mod you don't do for quite a while.