rcg33k

To answer your question... NONE! Just buy a good quality engine like a Novarossi, Sirio STI, RB, or OS V-spec. Modified engines used to have tremendous value because the manufacturers hadn't really learned all the tricks to make an engine go fast, and the lack of CNC machining made all those "tricks" very time-consuming and expensive to implement on a production engine. The advent of modern CNC machinery and CAD allows all the exotic cuts and shapes pioneered by the engine greats of years past, and it now costs nearly nothing extra – just a few more seconds of machine time.

Stay away from people that claim to be able to make your engine “SO MUCH BETTER.” The truth is, the vast majority will charge you good money to F-up your engine. The fastest guys in our area (which are generally the fastest guys in the world) simply pull the engine out of the box and put it in their car - no mods, no fuss. Engine modifiers will always argue this point because they want to believe they know something that the engineers at the factory do not, and wish to continue selling their “service.” Team drivers for said engine modifiers swing off the nuts of those that give them free engines, so they’ll always tell you they’re great (but somehow never manage to place well in any major event), and their customers generally want to believe the money they spent actually made a difference. Take it or leave it, but my own observations and many years of experience wasting thousands of my own money trying various modified engines of the Dremel generation has taught me one thing – keep ‘em stock and you’ll be a lot happier and have a little extra walking around money.