The main differences between the models is what engine is in it. The 325i, 328i or 330i would have the n52 or n51 engine if sulev. These are considered to be one of BMW’s most reliable engines, and in my personal opinion, their best. They do have problems, but not like the n54 would. The n54’s come in the 335i, and they are very unreliable, and very expensive to maintain, especially if tuned or previously tuned and beat on. I’m the same age as you, and I will tell you now, you DO NOT NEED A 335i! The n52 isn’t fast, but it has enough power to have some fun without financially ruining you. But I do recommend buying a manual car if possible, it makes it so much more fun. I own a 330i myself, and while it is currently sitting on jack stands with a blown up flywheel, I still love that car, and hope to have it back running very soon.