hello, i'd stick with your standard tank for now, but you can easily buy a fibreglass bum stop seat, although i'd see it in the flesh 1st before you buy it because alot will be too big for your bike.you may have to elongate it with fibreglass because alot are race seats, designed to be used with long aloy tanks. i'll guess you have 30mm fork stantions, but alot of small bikes with standard clip ons ie nsr125 have 32mm but they can be sleaved down. if by some chance they are 27mm, i have a spare set.