my 1990 ZXR750 maxed at 280km/h.. my ZZR250 maxed at 215km/h (with oversized pistons, ported n polished head n smaller rear sprockets)..

btw, i don't think u could reach high 300s km/h in the sepang straights.. for me, i juz managed 230km/h.. even a fren'z slightly modded GSX-R K6 could only reach 270km/h.. and, u wouldn't have enough road in msia highways to reach high 300s km/h.. and a txr panther that can reach 270-300km/h??