There are plenty of ways to be the fastest guy at your local track day. You could wrench like a mad man to get your spec Miata in top shape. You could spend a bit of dough on top-tier driving classes, and then apply your learned skills to your local circuit. Perhaps you have enough cash to dump on a dedicated exotic race car, which could help you set some quick times.
We have a better way though, and it means you're going to have to spend money on a Formula One race car... but you don't need to dump millions to do so.
Jensen Button's BAR Honda F1 car from the 2004 season is up for sale, and it can be yours for a little over $95,000. Now, that price doesn't include the engine, but it does include pretty much everything else. You can find race motors that will fit this chassis and still be well under the asking price of many new exotics.
Perhaps you're more of a Red Bull Racing fan? We have a car for you as well, though you're going to need to write a bigger check for this one. Mark Webber's RB3 racer from his 2007 season is being offered with an asking price of around $400,000. There's no word on if the powertrain is supplied with this one.
So if you're looking to decimate your next track day outing, you can do so in a F1 race car.
Mark Webber's Red Bull Racing Formula One car from the 2007 season