i dont think the GP can really pull of a euro look tbh.
euro is smooth, low and wide.
the gp is pretty smooth and sleek anyway, but i think the whole car is just too big, euro works on smaller cars imo.
small wide wheels with a dish, like 9j with a mad stretch on the tyres and sticking out the arches, or lower it with tuck, so the wheels are into the arch, but its hard to get away with tuck unless its a mental low tuck.
crystal clear lights. coloured leather interior is always a good one, with a nice head lining. if you wanna go proper euro, smooth engine bay with all wires and things hidden. euro is a hard look to pull off... it can sometimes go very wrong.