Funnily enough, we have totally opposite experiences :S
Optimax the car runs fine, gives (relatively) ok fuel economy, smells nice when it burns....
Ultimate it keeps misfiring, stalling at idle and gives really bad economy.
Bizzare huh?
So yeah, we use optimax.
My laser runs on whatever bowser I pull up at, be it optimax, LRP, ULP or PULP. Havent tried diesel yet, but I dare say it will run on that too ... 1980s ECUs give no fark for fuel. Or o2 sensor readings. Or more than one map. My ECU is no more advanced than some little chinese kid with an abacus.