yea a knew a guy that put a webber carb system on his 91 along with other mods and tuning... didnt impress me at all.
my intake/full exh. s4 blew by him everytime.
shouldnt be to hard to convert back just need lim/uim/plenum/tb/injectors/harness/etc.
where you located???? maybe i can help out a lil bit. i would give you some parts but i have sold all my s5 motor parts