1984-85: 318i, M10 4 cyl engine, cheap to buy but very little in performance, good gas mileage
1984-88: 325 "e" engine better but only 121 (128 for 1988) good low speed torque and good fuel economy. This is not a high reving engine even w/chip. Here, the 84-88s had the big aluminum bumpers.
1987-1991 (1992 if conv): Very nice 168 hp 6 cyl, very good performance, fuel economy about 20 mpg avg around town. Lots of goodies available from different aftermarket sources. 1989 -91 had the European bumpers in the US.
1990-91: Later model 4 cyl 318i, nice engine w/132 hp in 90 (138 in 91?) very good handling, less in standard comfort features than "i" cars. Early models had profile gasket problems that resulted in rapid cooling fluid loss. By this time all have probably been replaced.
Performance chips are available for all but the M10 4 cyl engine for added hp. All models use the R12 freon a/c system. I do not know if your Canadian models/versions differed to any degree from the US models. Rear shock mounts are a weak spot in all E30s. Replace w/ E46 mounts when the time comes. They drop right in and are stronger at a reasonable price. Good luck.