With standard gearing 45hp is about right (180-185kph) but once derestricted the bike is working too hard. 16tooth fronts are very hard to come by (Tuckerbag has found a source at reasonable cost) but seem ideal with the extra power. Puts you comfortably over 200KPH assuming you can reach 12000 rpm in top. 3 Tooth off in the rear sprocket should be a close equivalent although I would be tempted to take 4 off just for the giggle in trying to reach a silly top speed.