Are you doing straight-up trade or you adding boot? (extra cash) Have you ridden it? If it's unrideable because of throttle I'd be wary. How will you know if everything works? I'll bet it's been rolled, those aren't stock rear fenders, fronts have lots of stress marks, rad cover cracked. Look at steering hoop closely. Put front on milk crate and check all bushings, ball joints, wheel brgs. Then do same for rear.
What is his reasoning for trading a shee for a Blasturd? Throw some pics of Blasty up and list any mods.
If you get it fix that foot peg first thing !!
BTW, nothing wrong with a Blaster, my son has one along with the shee. Some mods and a little engine work and it's a lot of fun, rips good.