When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
If you are going 4inch for the exhaust w/ a borg I am guessing a S475. I am building one now w/ the billet wheel and new exhaust turbine. Should see about 700 to the wheels on E.
i only have a 71mm turbo i expect to peak at the very edge of 700 (efficency wise anyways) i havent got the billet wheel yet , but tempted