If you have the money for a new E90 I would recommend it for two
1) Nothing else new is going to give you the fun factor to at least
match your E30 combined with class leading refinement (I've never
driven any BMW other than E91 3 series touring
2) Have a 40 mile per hour head on crash in your E30 and you will be
lucky to survive, have the same crash in an E90 (or any other 4/5 star
crash safety modern car) and you will most likely walk away with a few
scrapes and bruises
Also try an E90 320d, mid range acceleration beats 325i, almost matches
330i and you should get somewhere between 42mpg and 50 mpg once run in.
The 320d is quiet and even sounds a bit sporty but lacks the 6
cylinder exhaust note (you can't have everything!)
Try to test drive an E90 with at least 2500 miles on the clock, mine is
"feeling" much better now that I have a few thousand on the clock.
Also drive it for an hour and a half or so.
Also do some research into run-flats before you reject them, they allow
you to keep control of the car if you have a blow out on the motorway
and free up usefull boot space.