If the roads near you are anything like as poorly maintained as around here then I'd definitely try to get a ride in a lowered coupe before lowering yours.
I've tried lowered springs with 16" and 17" wheels and even with Bilstein dampers the ride was still too harsh so ended up back on standard wheels and springs in the end.
Even had to buy a new set of standard springs as I didn't keep them when the lowered Eibachs were fitted and with my current coupe I sold the 17's that came with it and bought a set of standard wheels instead.
Maybe it's just a sign of getting old and cranky.
Also been in a lowered coupe with 18" wheels which had actually cracked the windscreen when it hit a pothole!