As Steve said , you should be able to pick up an HR for around £9k. I paid 9 something 12 months back.
First off, fit a decent exhaust system. This increases enjoyment levels 10 fold, but freezes yer face off, as you always have to have the window open for that epic chorus!
Then maybe a nice set of wheels and some suspension mods. It all depends on what floats yer boat and how big your wallet is.
Its the best car I've ever owned, and I love every minute driving it