The 31xi variant is 4 cylinder.
Inline 6 1JZ is okay with correct exhaust setup too. Not to mentioned the 1.5J upgrade.
Then again, you are right as turbo engine does not howl as fierce as NA, that is why I had a soft spot on V8 and above NA engine
Being 6 cylinder, 1JZ definitely has higher power output but more importantly, more linear power distribution across the rpm range. Maintenance is higher though. Extra spark plug and bigger block, if that matter. The twin turbo can be converted to single hybrid turbo.
SR20DET is a potent engine too as it's standard power output already dwarf those of stock 318i variant of E36. Marginally higher than 325i E36 too. Should be no issue on lack of power but fuel efficiency is very much determined by our right foot @ driving style.
Turbo spooling sound can be addictive, and that will encourage your right foot to floor at every chances
The choice is yours. Best is to test drive / bring someone with good knowledge on cars to check out the condition. Turbo engine has much advantage and wider playing field over the NA car. Especially on lower displacement car. Reliability is much depend on modification done, tlc and again,
right foot
