well i think the maintenance for e46 and e39 ---->
abt the same bro .....1 litre diferent (engine oil)
but e46 has lotsa stuff to modify compared to e39...so u might get burned as well when u purchased a e46....
Previously owned an e46(330i-sports) and e39 as well...and i agrree with Geoffrey that if you plan for e46, go for the cabrio.....type... cun ma....can pick up also..hahaha
Hope that helps.........
cheers