Difficult choice buddy.
I also do high mileage (100km+) a day and to own a BMW is not a cheap vehicle for an everyday high mileage runner.
The 330i is the better 'engine' here and the E46 still looks lovely, but if you use your head, the E90 320i sportpack with MP would be a better option long term. Consider maybe an E90 325i if possible, I think its 160kw and the E46 330i is 170kw. You'll get a nice blend of power and new looks there:thumbs:
Reliability I think the 330i is the more bulletproof motor and maintenance overall will be cheaper on the E46, only servicing will be more expensive (6cyl vs 4cyl)
Drive both, write down pro's and cons, etc and make a decision.
Whichever you choose, welcome to the BMW family man:bravo: