It's the worst of both worlds, I'm afraid.
I'm currently riding a 1993 GSF250R (after they dropped it from 45bhp to 40bhp). As you can see from the dyno, 40bhp = 33.2bhp at the rear wheel. Police and insurance companies go by company specs, which are measured at the crank, so I'm afraid if you want to ride legally, you're going to have to cough up the £150 for the restrictor kit. Bitch, I know.
Btw, I live in Leicester and I'll be selling mine soon, if you're interested. It's got the 33bhp certificate, but I... lost... the restrictor kit