I've had a couple and they should fit. It's the spring rate / free length that will change. I can tell you that the damper free length for the marea 20v saloon is ever so slightly longer than that of the coupé.
I think it's worth a try if it's not going to cost you much. I think you may find it too stiff or that the rear end sits too high.
Re: Will Marea rear springs fit on the coupe?
[Re: NikAzwaa]
#1319707 26/02/201212:5526/02/201212:55
Had them fitted. It fits perfectly. Feels better too. But height-wise, it's almost the same as stock springs. Maybe needs a couple of days to settle in. It was worth the shot.