I have walked your path, with your model se7en. Doubt clam removal will do much, but just a guess. My X-flow topped out at 105-07 mph and wasn't fast enuf to have lift. Brooklands in place of full screen helps a little, ditto turning headlights sideways. Some have reported a bit more speed w/top up, sidescreens on.
Engine upgrades to X-flow-are expensive and add modest power. For $10-16K you can buy a BDA that drops right in (and makes same hp as a $1K Duratec).
FIA bar is huge safety improvement, same for seats with anchor strap for 5-6 pt belt.
My odessey included upgrading to a much higher hp Birkin and finally a full toot, track only Caterham, w/cage, fuel cell, Zetec, etc. And both later cars were/are much faster than the X-Flow. Are they funner-actually, that's a pretty close call.