help needed with 904

I know I'm putting the carriage before the horse but I can't help my brain! It's always thinking ahead to The Next Step before I even get anything else done. So I'm definitely if it's affordable and possible wanting a manual valve body. I'll give you my reasons because lot of people don't like doing stuff without knowing why like myself. The car is a total toy and fun and for entertainment so having a full valve would not be Troublesome as a matter of fact it would for the cars intent purpose be welcome. ( just kind of being a badass nasty car)
Soooo any cheap suggestions? Not so cheap that it will blow the transmission up in 20 minutes but you know... get the job done?