The Kelo Exhaust ring interferes with the sparkplug caps so they get twisted 90º. Loosing the little locking wire at the bottom of the cap. I drilled a small hole in the fin. Then used .020 safety wire to loop around the cap and it holds without issue. Its not tight just prevents the cap from coming off. After 15 flights or so the firewall let loose and I landed the plane with drama. It is repaired and ready to fly this season. My delimia is do i put the MMM timing ring on a perfectly operating.