if i were looking for a bigger car i'd just sell up and buy another motor.
it will take time for the prices to rise and in that time the car will need attention, especially being locked up in a garage unless you are heating it and rotating tyres frequently.
as for insurance, whip the engine out and it won't technically be an auto-mobile as it has no way of being powered and should be covered with house insurance.
the choice is ultimately yours, i have a daft xr2, but between myself and the wife we also have a 206 xsi and a bora tdi sport, so a sensible family car is always at hand. I'm not sure i couldn't have the xr2 if all i had to hand was a sensible family car.
tough call, but there are still plenty of good rs's out there.