Got most of a sectional garage stacked up in my garden and a loft / shed full of Ducati and Yamaha parts which barely leaves any room to move in. I've also have an 8x4m hole dug in my garden for ages filled with hardcore and aggregate waiting for some expensive concrete to be poured on top. Apparently I'll need 5 cubic metres of concrete which equates to over 100 wheelbarrow's worth + my garden is about 60m from the front, up a slope to the 'garage' - this will definitely require favours to be called in!
I sort of understand what calum is saying. But personally, I'd run it by the numbers. I have no experience with rolling roads, Dynos and rebuilding engines etc... But I have plenty of experience with getting the maximum of performance out of computers. Now you can build yourself a nice rig and all and it can run your programs, engines, games or whatever absolutely fine. But if you don't tune your rig and set it up properly, then you're just losing some of the extra kick. And in which case, I then have to go and run the numbers
If you're happy enough with a smooth ride, that's fine. If you want to push it to the limit then you'll need the numbers.