If i may make a statement for the opposition..... ahem
I'm building a track day only car as the last car project i did (Ford Capri) never got any regular road time (except when my daily driver broke down). It really bugged me that all the time and effort I'd put into getting it through it's MOT, all the money I'd spent taxing/insuring it was going to waste while it sat in the garage. It did less than 1000 miles in a year, so I sold it.
I decided from the outset that my locost was going to be a track day animal, If it was a road car obviously the build is more difficult, IVA costs the same if not more than a years insurance - or for arguments sake, more than 5 track days at £100 a go. And when it's finished, it requires no annual MOT and no tax/insurance, so if I don't use it for a month or more - it costs me NOTHING.
I know when the time comes to sell it, it won't be worth as much as a road registered equivalent, but that has never been the point in me building it.
I know track use is hard on brakes/tyres and the like which means they will be replaced more often, but that will probably cost less than the fuel to use it on the road regularly.
If you are going to build a car that has such performance, and only ever drive it on public roads at legal speeds, maybe your wasting your time, get it on track where you can really unleash it. And for goodness sake don't fool about on the roads, cos that's just plain stupid.
One other major consideration I had, once you spent all your time and money building your car, how comfortable would you be parking it in a regular car park and leaving it all day? What if somebody damages it, or worse, it gets stolen?
So, my vote is track use only.