i need 3 series naming breakdown info

looking to buy a E36 3 series and im not sure what all the numbers and letters mean in the 3 series names. i know that the M3 is obvioulsy the ultimate 3 series but i am also looking at a regular 3 series. i know that some come with a 4 banger and some came with an inline 6. just wanted to know that if anyone can tell me about all the names or proved a link that will explain the naming system of these beemers. thanks all.

The e36 has numerous models. In the us we have the 318i which is the 1.8 liter 4 banger, 325i is the 2.5 liter 6 cylinder. The "I" just means that it is electronically fuel injected. In 1996 or 97 they built the 328i which is a 2.8 liter 6

Generally the last two numbers are the size of the engine in liters. this is not always true: for marketing reasons bmw posted the 99-2001? e46 3 series a "323" which is actually a 2.5 liter. That way when buying the extra$$$ for the 328 over the 323 it seems like your getting a lot more than if you decided between a 325 and a 328

thank you very much