Well the car is only 1000 kilos... which sounds bizzare but its light for a car =P
As for the flywheel, i'm not so sure of the weight. Its not for a gain in speed for the car its for a greater driveablity. I like a car that revs nice and freely. I wouldn't go mad, just enough to rev up quicker but not so much as I'll grind to a halt every time I'm on a hill.
My engine doesn't produce a lot of power, 100 bhp if I'm lucky (with the airfilter thats on it now), so rather than soup it right up I'm more concerned with the car using as much of that power as I can make it
A remap, full stainless steel exhaust system, airfilter and fast road cams is a LOT of expense for maybe 15 hp in total. And then I'd have to go about sorting out the handling.
I'd much rather lighten the flywheel, drop it, bigger tires on it, quick shift kit. Yes, there's no horsepower gain but there is a car which is set up for my driving style for not as much money. And we all know that you can have all the power in the world but if you can't get to grips with the car its useless. A driver friendly car is worth its weight in gold. (Audi Quattro rally car as an example. Only one man could get in that car and drive away. Any of the other drivers couldn't handle it. It was set up for him.)
That way I can do the other stuff as and when tho older parts are done like the exhaust and i don't need to go around uprating everything... its already done! =)
And yeah, I'm not so good with machining equipment so it'd be getting sent away for a pro to do it.