I've not personally tried any seats in my car yet tbh.
But the one in that picture is not suitable. If the buckle touches/lies across any part of the seat frame which is facing forward, then this is classed as buckle crunch.
Basically in an accident the plastic/buckle could brake because of the forward force of the seat. If this happend the seat could then come loose and fly forward at speed.
The Britax First Class seat is designed to fit the majority of cars, especially those that suffer from buckle crunch on alot of other seats. This is because it can be fitted an alternate way. I have one for the womans Beetle, but seeing as the baby isn't here yet, I haven't tried it in the Supra.
Unfortunatley not every seat fits every car (which is what people honestly think!)... people tend to buy seats because they "like the colour" etc.... but 9/10 times the seat isn't actually suitable for the car!!
Best bet is to goto somewhere like halfords, and the fitter there should take out seat after seat until they find one that fits.