I foolishly stripped out the plug thread on my PTE36 when I loosened and tightened the plug while the engine was hot. Doh! Lesson learned. I went ahead and paid the astronomical price for the M10 X 1.0 heli coil kit since I have some Super Tiger engines that I am going to convert to gas and I want to use a CM-6 plug instead of the tiny 1/4 - 32 plugs. My question is, should I use some sort of sealant like red silicone when I screw in the heli-coil or will it do a good enough job on it's own?

Not normally needed. The sealant used should stay flexible enough for the helicoil threads to "work" as they are loaded.

Blue Loctite helps lubricate the coil when you put it in and stops it moving later. If you put it in dry, they can curl up as you install - then need pulling out again.

Smack the tang hard when you have the coil in. Don't go gently or you can bend the end up and thus it needs pulling out.

Once 'in' to your satisfaction, they are bullet proof [8D]

Thanks for the responses. I'll put a dab of loctite on the insert.