05' 450 SM (Looking For Gaskets)

[DutchSM450]

last year i bought a 450SM 05', and i've been enjoying it ever since the bike only done about 5000KM (3106MI), but i've noticed the gaskets are staring to degrade so its i'd say its time for a ''Tune-Up''. i've been looking on the internet for the past 3 days or so trying to find a gasket kit for the 450sm but i've had 0 succes.....
so my question is
1. what gas gas 450 share the same engine as the SM 05' (Are fse/FSR the same?)
2. are there any bikes that share the same gaskets? (i've heard DRZ 400 are simmilar and wr 450 aswel is this the case?)
3. are there any site's that stock parts for these bikes?

help would be much appreciated, since i'd love to keep this bike but if i can't find any parts i might have to sell this bike.

thanks in advance
your friendly Dutch rider