My way of thinking is only a short area like the IoM where you're going to be covering shorter distances than long motorways and dual carriageways in the UK, there isn't really a whole lot of point to a tiny bit extra bhp, torque, air to the wherever etc.
I just think there is a limit to how much is usable for day to day driving. When you finish work at 5-5.30pm on Friday and are heading along Central Prom, no matter how many horsies you've bolted to your lump, you're still going to do 10mph like the guy in front of you and the guy behind you.
And I'd love to get my hands on a good Scooby, I really would. But the things is, information these days seems VERY hard to come by!!