I run the S12 H190 diff in my race car with SR20DET - works a treat.

You will need to change the pick up points for the lower trailing arms, but the top ones should be fine. I is much wider than the standard diff, so you will actually need wheels with a much larger offset. I run +24mm offset on mine, but I also have 50mm flares & 225 tyres. Even with +45mm offset I think you might struggle to get them under standard guards.