I'll put mine in for the Shoestring. The string is fast but it will also do what CTLflyer is requesting. It's fast as it is agile, thus allowing for aerobatics. I'm running the TH .75 in mine and it screams. I replaced the stock muffler with the pitts made for the OS 91FX, modified to fit the mount on the .75.

Other modifications I made for aerobatics,
Added right thrust and moved the CG more Aft then instructed by the manual.

Blackie