Just doing some more gearspeeds with a more sensible 8000 rpm limit
235/35/18 aren't available in r888s so I'm going to assume I will have to run a 225/40/18

3.54 diff is 206 mph
4.09 diff is 178 mph
4.55 diff is 160 mph

So I think if I'm going to have one the 4.55 will be best, and it will bring first gear down from 59 mph to 46 mph

160 mph at 8000 rpm is 20 mph each 1000 rpm, so 70 mph at 3500 rpm isn't to bad either for cruising