Welcome to the best seadoo site on the planet!
Well you did the right thing by joining here first before you buy. Older jetboats can be major money pits so make sure you do lots of reading before you buy anything.
#1 thing to know about jetboats...jetboat specific parts are scarce!! There are some things like control cables they finally started remaking in the aftermarket, but things like the MPEM can be over $1000...used!
twin engines mean twice the parts. They are a ton of fun, but if they need carb rebuilds its x2. Two motors to worry about.
If I can help further just let me know. My brother has one of the bigger collections of used boat parts.