We've always had great luck with iShock, and they're good folks to deal with. On the comment that all kits are the same, I have to differ there. One easy way to tell how well the kit is desinged is to get in and do a tight turn. A LOT of kits out there will plow and not want to turn. Quick and easy way to narrow things down a little.
Have to agree on HRT, their stuff is definately proven. Ask Todd, and ask Regis Harrington. He took first for us in the M4SX series, and placed pretty well in CORR running HRT's setup. They're also great folks to work with. And Chris at Benchmark builds one bad ash motor.