ok, so my neighbor picked up a 1992 saab 900s convertible. it needs a new top. is it hard to do? i've never even looked into replacing a vert top so i have no idea. if its just nuts and bolts, i'm pretty mechanically inclined so i could probably figure it out. however, i dont know if there are any special tools needed, any particular way to make measurements to assure its even, etc... any help is greatly appreciated.