I spoke to the fast ford bloke yesterday, and without doing major mods to my engine, there's not much point in the lighter flywheel so I'll save my cash. I have lots of other goodies I want to buy 
I think you have made the right decision. Lightening and balancing the flywheel and clutch assembly on a tuned engine will undoubtedly help the drivability, but then again if you have such an engine you will be driving more in the upper reaches of the rev. range and using the gears a lot more to stay in the power band. I had an engine in a similar state of tune to Dave Collis in Canada, a few posts above, fitted to a Caterham Seven and had the flywheel machined at a local machine shop. They took off as much as they could, for a not unreasonable £25 or so (this was over 20 years ago) and it made a huge difference. It revved easier, gear change blips were better and it slowed the car quicker too, all as per previous posts, but I think it would be a retrograde step on a standard engine, especially in a heavier car like a 4/4.
