Hey bud,
Do it!!! Get either and I am sure you will be happy. Take out a 2 year unlimited km warranty to assist when the car is being a pain but other than that any used car or car that you will modify will give niggles and days you want to burn it etc.
I came from an FN2 Type R and holy shit what worlds apart, power wise and the way the car feels.
I have a 2011 E82 N55 135i DCT. I looked over a year or so for my car and I am so glad I got one spec'ed and coloured the way I wanted.
It is almost fully spec'ed with Idrive, PPK, BMW PE, gold calipers, carbon fibre bits etc and I can say this car is one of the most amazing cars. Every time I drive it I have a smile on my face haha.
With the Type R I was getting like 12.5l per 100km and with the BMW I sit on +-13l per 100km when I am not in sport or/and manual mode, then it can see 18l per 100km but I will live with the fuel consumption any day for the way these cars drive and tell you they will hurt you if you are not careful.
Me personally, I couldn't hold the mod bug back and ended up doing JB4, DP, Intake, Charge pipe and Stage 1 hybrid in one go :smilebounce:
These cars turn into monsters when you open them up, so N54 or N55 you will be happy and before you know it you will have the Pure Stage 2 turbo page as your home screen because there is an itch and you know its wrong to scratch it, but it whispers at you when you sleeping and eventually bam you have 500rwhp and its daily driven.
Do maintenance on them and when something is not right get it sorted out. I had the PCV and front crank shaft oil seal go which is a big job and pretty expensive but you must PAY TO PLAY :fencelook:
Good luck on your search.
There are many knowledgeable guys out there who are always willing to help and advise and sell you mods haha.
If you are unhappy with the car or it was not what you wanted sell it and move to the next one but these platforms you need to experience at least once!