Mate at work is looking to get an MPV. He needs something "reasonably" priced. If I had no other choice I'd get a Volvo T5R, plenty of space and still enough grunt to not be a complete failure.
the GSI or VXR zafiras are pretty nippy and can be tweaked up quite a bit but 600 is some serious mods! Im only on to page 2, but with 250+bhp im gessing its a mk3 or 4 with the 2L red top, my cuz's hubby has a mk3 running 250 which is pretty quick, but it can be chipped upto 300+ quite easily
My old neighbor who now works at Audi has a 400+bhp astra, proper sorted with all the right bits, those vaux boys like big power as much as anyone else. Edit: Also Opel did a hot Zafira with 220bhp iirc