The Mono by Briggs Automotive Company Ltd.: 280 HP, which means 520 HP/ton (for reference the Veyron is 523 HP/ton)! 0-60: 2.8 seconds, Max Speed: 170 MPH, and the cost £96,495 base plus customization fees, VAT, shipping, customs duties, and local taxes... Still an amazing vehicle, and road legal to boot.
Marlin SportCars, 5exi, performance oriented mid-engined roadster. Again, this one is hand built to your driving specs. Race/Track/and road versions are all available. Engines offered include VW, Honda, and Rover. Spec'd with a Supercharged Honda R engine: 0-60: 3.5 seconds, and top speed of 165+ mph. Pricing starts around £18000