Of the 2 cars the rear end of the Sei is nicer, the front of a Cinq is better, (even toyed with idea of trail fitting a sei rear door and seeing what’s need to fit it permanent as there should be little in it) side profile of cinq cleaner as the rear quarters on the Sei are like a lot of modern cars are too thick and obscure rear vision, and in my eyes is clumsy and makes the rear end of the car seem higher than it is because it raises the waistline of the car.
I have to say the dash board in a sei is an absolute abomination, so much so that I considered a Sei to put my turbo engine into but I would have changed the dash boards over as well as having a rev counter over to the left is just nonsense, plus no temperature gauge is a no no, its like an afterthought.
The engine bay is tidier on a Sei as the area all around the ECU brake servo is much neater.
TBH, all the comments about Seis being smoother is only with regards to the MPi model, as the Spi I have been in felt exactly the same as a Cinq Spi.
Aaron.