IMHO, the choice is obvious--E39 525 or 528.
Speaking from personal experience, as I own an E39 (CKD 523i), the E39 handling is fantastic, 2.5 liter is also not bad, as someone who loves FR sports cars, who drives hard, this is one car that always put a smile on my face.
In addition to the wonderful handling, there is a lot of room for passengers too. Now, let's get back to the sporty part...
My E39 smoked many C200Ks on the highway, it is extremely stable at around 220+km/h. Coupled with a responsive Steptronic, this thing just rocks! My buddy's E46 was a little nervous at speeds over 200km/h. The tail just didn't feel well-planted. I don't know if it is just my buddy's car, or all E46s, but the one I drove certainly didn't inspire confidence.
C200K is not roomy enough, slow, and has quite a bit of electronic glitches... I don't think it belongs in this league, sorry.
Good luck on whatever you choose