sport bikes? OK here is the deal Ive been riding my 04 CBR600RR for about 2 years now... I can handle the bike with ease and i got the wheelie down smooth.... But i want to start racing on the track and i dont know if i would like riding a bike with that kind of power competitively. so what cc should i start out at? Im 5' 9'' and 155 pounds... also what bike would you say? (buying used)