My vote would be the X1 xDrive35i. Best compromise between all major factors. Small like the M235i, got the N55 engine, AWD, spacious and more practical.
X5M would also be a good option but original S63s are horrible motors for what they are. Definetly better than the N63 of the time, but not by much. Only get a X5M E70 if you are willing to deal with the major issues these engines have, including rod bearings.
E90 320is never came with a straight six. At best, these came with some form of NA 4 Cylinder. All other models after the 320i came with some form of 6 cylinder. 320ds also come with 4 cylinders, though these were turbocharged. Unless it was engine swapped, I would be very skeptical.
Seller doesn’t state how many KMs the car has done, so that is also a red flag, unless it’s shown in the pictures.
I would stay away from this one unless you are looking for a project car, and are willing to gamble the whole way.
Most prevalent issues include, but are not limited to, thermostat failure, VANOS solenoid failure,hydraulic lifter failure and water pump failure. These jobs can get very expensive very quickly if addressed late. It is recommended to do these jobs as preventative maintenance before these compound issues over time. Ideally, you’d want parts with warranty, so have a look at FCP Euro with their lifetime warranty.
Other issues primarly revolve around gasket leaks. No real fix to these. Just got to stay on top of them before they turn small issues into big problems.
Out of all the engines, bar the diesels, the 630 is the pick of the lot. The gearbox is kinda the Achilles heel of the whole deal though, though this is true for the entire E6X range. These cars are generally reliable for the most part so long as maintenance is half decent, and all major issues with the N52 are addressed.
It’s been a good while since I last worked on a E63, but IIRC the transmission can be remapped relatively easily to make it more easier to drive on a daily basis. In some cases, the flash improves fuel economy, depending on your commute.
That said, the E63 has other issues as do other BMW models from this era. Most are electrical issues that can lead to more severe things down the line, like a old battery causing the car to go into limp mode due to low voltage, or the steering rack locking up or becoming heavier than normal due to the pump dying. Other issues include the headlight computers and the ECU. Most of the time, this is due to faulty wiring running to the ECU.
There are a few other issues, but I can’t think of them at the moment for the life of me. These issues are to be expected, as this is an older BMW after all.
Always