I think when you try and combine a road and track car, you compromise both too much. Road cars can be fun on track, and track cars fun on the road, but ultimately you have to pick a direction and maximise the car for that. I get that not everyone has the cash to do that, and I feel fortunate that I have been, but if you can (even if the track car is worth 4p and all you've done is strip it) then you really should.
All I did to my mx5 was strip it, add bucket seat & steering wheel & harness. No suspension mods, no power mods, just weight loss. Apart from the lack of power on a longer straight, it was a hooligan of a fun car. Sometimes just removing the weight and sitting in a tin can is all you need