If anyone has experience replacing soft top on S2000, can somebody with not much experience do it by themselves? Is there any manuals?

 

Aside from the Helm manual, there's a '00-'01 to '02+ top conversion how-to in the FAQ's of the "Under the Hood" forum. It will give you all the info you need to replace the top, conversion or otherwise. I replaced my top by myself with no experience with convertible tops at all. It wasn't easy, but if you're patient(took about 8 hours total) and somewhat mechanically inclined, you can do it.

 

you can also choose the easy way out and do the swap with frame/motor from a 02+. But no sure if there any instruction on how to remove soft top