If your Plus 4 has got 195/60R15 tyres you will have less than 3.5 inch clearance.
I always jack from the rear under the centre of the rear crossmember, there's a good 6" or more of clearance on my 4/4.
Good point about a flat tyre, though. When I've had a puncture I've always used the scissor jack from the toolkit to get the car lifted enough to change the wheel.
