Faster
Have you considered Lancair?
The pre-built Columbia cruises at 219 mph for $300K with full avionics (turbo model for $350K cruises at 280 mph).
Kit models include the IV - 335 mph, about $220K complete (of course you have to put in 1300-1500 hours of building), and the Propjet IV which will take you along at 380 mph.
I know, still a lot of $$ and building isn't for everyone, but nice to dream about.
My personal favourite is the Seawind, a 200 mph amphibian.