Lets dream a little here & ignore the need for a cert here in NZ (Gearbox X-members modifications)

as I've temporarily misplaced my 3rd & 4th gear in my Racecar
and I have managed to pick up a Auto Bell housing to get the process going
ok the Ford type 9 / Sierra Gearbox seem popular


the above is in a MG Midget
and I am aware Miles has a Toyota box of some kind
think out loud & what kind or source for any Gearbox would you go for? (power / reliability / ease of parts & Instalation)
From unlimited budget Sequential air shifted dog box to the simple Home handy man with limited Engineering skills

Lets hear your Ideas & why they are good I'll paste a few liks to threads alread on this Forum below with existing awesome informations