Bearing in mind what skruntie has said I adopted the same approach as I did with my "meatier" Volvos, a compromise between performance, economy and cost. Toyo Proxies CF1 fit the bill for me, I've just put a pair on the Miggy, 205/65/15 are £68 fitted via BlackCircles (and they have a handy ridge to help stop you kerbing your nice alloys).
Search here;
http://www.blackcircles.comWith the company/lease cars (Volvo FWD) I've had then it was a case of factory-fit replacements only. In one case this was Continental ContiSport, which wore well but tramlined and were noisy, and in the other it was Pirelli P6000's which I hated (tramlined horribly and awful in the wet, spinning the wheels in first 3 gears in a manual diesel!). I ultimately bought both cars and (when it was time to change) changed to Goodyear Eagle F1's which transformed them.
It IS the only bit that meets the road and you can only save so much before it becomes a false economy IMO. BlackCircles have regular deals which can save you more on certain makers and you get points to go in your "tyre bank" redeemable against future spend. As you might have guessed, I'm a big BlackCircles convert but there are other similar sites just as good I'm sure

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I've also had an Enduro fitted - whilst I was travelling and had a blow-out (spare had gone flat

yes, I know.......). ATS came out to me on the motorway (after instructions to bring a budget tyre) and fitted one of these for around £65 (budget....my ar$e!!) I think it was 225/45/17. Wasn't bad, didn't unbalance the car and is still in service on the spare on that car as far as I know.