I bought them through Stephen at IA. They are Mahle USA and had the coatings done. I was going to do a 3.4L but stock compression instead, long story. The reason I stayed 3.3 and stock compression is because I didn't think twin plug was worth it. I was getting tired of spending big money on little results. With stock compression I can run pump gas and more boost safely. Though I still mix gas when running 1bar. If I had money to blow I would twin plug, it's better than single plug in any case.

Think about it, by the time you modify the heads, twin plug distributor, wires, spark plugs and labor you have just spent like $3k on top of going 3.4L and 7.5:1 CR which is alot of money to start with just to be safe with the bump in compression. Talk about getting snow balled in spending money just for better throttle response and about 10 more hp, I DON'T THINK SO!

 

I purchased mine from Engine Builder's Supply. I originally purchased the RUF designed Mahle short skirt pistons, but in my application, I really wanted the longer skirt. Check with PorschePHd, he has some good prices on them.

 

Brent930,

Yes I am running the 98mm P&C kit of 7.5 compression from Ruf which are actually Mahle but just short skirt and at 0.9 to 1 bar of boost. I've not done much mileage, about 10,000 miles and tracked my car very little. Mostly street racing. However my friends with the same setup have been tracking their cars often over the past few yrs and no problems when one of them tore down their engines recently to another another upgrade. You are correct, that if you dont have good gas than you cant boost high. Here in Singapore we have Super 98(RON) so we're ok at 1 bar and 1.1 bar only for a short burst with the fuel enrichment that is.