His other option is to get a 125i MSport and wait just a few more months until the chip tune is available for it. (125i=160kw, chip upgade to 210kw with Exhaust cat back changed to 75mm) or wait a little longer and get the proposed M performance chip for the 328i.
As the engines are the same (different exhauste) It should be possible to modify the exhaust and use it and take it up to 255kw with the same exhaust size upgrade as 3 er. Then look out, a beast will be born.
It may only be a small difference in price between a 125 and a 135 in the UK.
Once you add the extras onto each (5 door version) it is still a considerable difference. (in Aus it is a $16,000 difference).
I would have the 135i if we had Autobahns here in Aus, alas we do not, and the speed limit is 110KPH, so most driving is around town and some small mountains. I prefer the 125i M Sport for that.