There are 4 types of e30 325. The 325, 325i, 325es, and 325is. The 325 is the 325e, they did NOT mark Es on the cars. If you have a plain 325 marking its a 325 e, or eta. The 325i is the exact same interior and electronic features as the 325(e). The 325es was a special model only made for 2 years which includes the sportier suspension, rear heckspoiler, trunk mounted battery, upgraded OBC, sports seats, and last but only best, Limited slip differential. The only thing it didnt have was the IS basketweave rims, just the 14" bottle caps. The 325is is everything just mentioned with nicer wheels, and of coarse the I engine.
Now as the engine differences... The E or eta (which means efficiency in greek) was a high torque low reving, fuel effiecient engine for the post fuel crisis era. It has 120 hp and 170 ft/lbs of torque and redlines at 4750rpms. It uses the same transmission but has small rear diff gears, 2.91:1. It uses slightly lower compression pistons (8.5:1 ??? i forget) , and the crank from a 528e, making the displacement 2.7 liters.
The I engine is a nice middle sized, middle rev band power engine. It is a 2.5 liter engine with 8.8:1 compression pistons. The redline is at 6000rpms and is paired with a larger 3.73:1 rear differential. This engine makes 168hp and 160 ft/lbs of torque.
Both engines are great, in my opinion the I is a much better all around engine. But the E is much better for tuning and upgrading. By chipping it the redline can be increased safely to 5000rpms. New diff gearing will be a major kick in the ass powerwise. Breathing characteristics are more important due to 2.7 liters. Cam will provide extra power go weee. Im spent.
<span style='font-family:Geneva'><span style='font-size:14pt;line-height:100%'><span style='color:red'>Fox</span></span> <span style='color:gray'>the Pirate</span>
Diplomacy is saying "nice doggy" until you find a rock.</span>
I live my life one quarter mile at a time, and for those 23 or more seconds I'm free.