does anybody have experiance with the slimline [link]http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXFG90&P=SM[/link]

Yes, but the one you've listed isn't a pitts style. For that look at this one... http://www3.towerhobbies.com/cgi-bin...?&I=LXFH36&P=7

In any case, Slimline mufflers and support are top shelf.

sorry i ment to say the sport scale. oh and would that combo fit in a 4star60?

My experience with Slimline mufflers has been that they tend to cause overheating because of the small chamber. Are you trying to route the exhaust under the plane?

I have a Slimline Pitts muffler in my Venture 60, which is very similar to a 4* 60. I have an ST .61 mounted sideways in a cowl. A bit louder than a stock muffler, but it runs great.