Originally Posted by
az3579
I have experience with both platforms - my ZHP, an E39 525iT I used to own, and my brother's 540i 6-speed from back in the day.
The driving experience will not be comparable. The E39 is bigger, softer, quieter, more refined, andheavier. The steering of the 540i is a weak point as it uses a recirculating ball setup, and I personally didn't like it in my brother's 540i. Otherwise, the torque and sound is nice. It's more antiquated with regards to the electronics compared to the E46. E39's are quite nice to drive, but they're not exciting.
The maintenance kind of sucks on those V8s, so be prepared for that. Personally, I'd go with a 530i as that has the better steering setup as well as an easier-to-work-on engine.
IMO you're going to regret getting rid of the ZHP. Most people do. The E46 is just simply more enjoyable to drive.