and lastly, if i use SL forks on the front without any modification, how much will lowering the front like that change the riding characteristics?
substantially. and none of it good.
here's the qualifier that i also posted up during your recent "red loctite on spark plug threads" dead cylinder situation.
NOT intended to criticize but intended to avoid potential catastrophic results: your historical postings indicate you have neither the skills, tools or knowledge to perform showa cartridge fork work. google "showa fork rebuild services" and find an outfit close to you OR call a local dealership/dirt bike specialist and see if they'll perform the cartridge and tube swap along with anything else needed. money well spent...isn't terribly expensive...work not for the novice.