I've looked into extrude myself...And I'll concur with what Duffy stated...I'm not sure that it's worth the money spent. An example is the IC tubes...$150 each or $125 with a club discount. So for $300 (or $250) you can get the 2 of them done...How much will you pick up? Not much. I opted for doing some hand grinding myself then had the blasted with aluminum oxide to smooth them out. You would be amazed at the difference there! I'm not sure that I'm going to get flow #'s simply because of cost, but they will flow more. How much has yet to be determined. I'm not expecting a great gain, but $30 is much more reasonable than $300! Now heads are a bit different. I've spoken with Bob Steigemeyer about the extrude hone, plus some local machine shops. The problem that they have had with the extrude hone is the seats for the valves. That is steel and the heads are aluminum, so the ports will hone more than the seat leaving a "lip" at the seat. This is a place of restriction as it causes turbulence. Now, this is coming from people who port heads for racing teams, so take it for what it is worth. If I were to get my heads ported, I'll go for a hand job simply because I want the most for my $$. Now when it comes to a manifold (with real runners instead of the SC open design) then I could see where that would be worth it. I just don't see too many places where it would be worth the extra cost on the SC engine.