If you wanna think a little different, have a go in a Holden GTS. Its essentially a big Omega, but it has a 340bhp 5.7 litre V8 and six speed 'box from the Corvette ZR1
They're also quite tuneable - my old man had a blower bolted onto his from new by the importer (Linden Special Vehicles) and its now producing 532bhp and 500+lb ft of torque.
There's only about 120 of them in the country, so you'd be driving something that your average man in the street wouldn't see everyday.
Basically, you've got a fast, comfortable, spacious, driftable, rare motor. Its essentially a reliable four door TVR! Find one and have a blast, should be able to pick up a standard GTS for that moolar, no problems.