i get roughly 11 in the city, and 30 on the highway (yes, 30...three, zero...did that with a road trip to O-town)

id go with a 6spd over anything....i had auto, and blew em left and right, then converted to 6spd and am loving it.

problems-
opti, plug/wire changes (headers make it easier), never heard of the headgasket oil leak, there is an intake manifold rtv gasket leak though, right by the EGR setup, EGR seems to get hot and burn up the gasket or something. 93-94 have unvented optisparks.

good news is, they sell coil pack conversions for about the price of buying a new optispark, took me about 2 hours to do my intake gasket change with "The Right Stuff", and blocking off the EGR is simple.

as for the fuel sending unit jumping around, when i did my fuel pump change, i bent the arm slightly to read ~1/8 tank less. that way i dont have 6oz of fuel left and it says 1/4 tank. being someone that came from a 1G AWD car, i was very impressed with the stock power of the LT1...the torque difference was very noticable