Will you be happy stepping back into older cars with more dated tech and interior, not that the cars mentioned are notably bad for this but 2005 design car compared to 2012-2013? is going to show a bit.
The BMW will only take a tune unless you remove the DPF whereas the petrols will be more straightforward for tuning, maybe have a look at the F Series 330d with the better 8 speed auto?
I'm not one to be passionate about cosmetics, i.e. what the interior looks like, tech, etc. If it is good quality and generally a nice place to be, then that's okay with me. I've snooped around an E90 and yes, it is a bit dated but nothing that bothers. me. I'm more interested in what is going on underneath, i.e. the engine/transmission/how it drives.
Any car I get, the max. I will mod is a remap/exhaust. Nothing more.
I have looked at the F30s and these are over the 20k mark and I don't really want to spend that much! I do like them a lot but it's pushing the budget quite a fair bit.