I'm not sure if the prices are they different.... I'm sure you would have a choice of either if you are getting finance.
The 328 is noticeably quicker than the 325 despite minor power increments.
I'd got for the 328.
Just for your info, BMW's aren't always the best cars to modify...... and visit your bank manager before taking finance from a dealer, you'll get it cheaper.
Good luck and let us know!
<span style='color:blue'>"So my BM makes me a flash bastard? Then I guess you're just keeping it real from the seat of your nova?"</span>
<span style='color:gray'>"...and the home of the brave..... is bravey 130bhp from a 7 litre engine? 100bhp/litre or don't bother building it!"</span>
<span style='color:red'>"Aaahh the UK; where every road is jammed, under construction, poorly maintained and unfairly policed, at least we don't get over-taxed for it........ HA HA HA!"</span>