[RobUK]

Drive both and then get whichever one floats your boat.

I don't subscribe to this 335dx 'killing' the 335i in performance thing - yes on the track I'd say yes that might be a relevant argument if you're chasing lap times. On public roads then you'd have to be pretty much ragging it in both cars for that to become a meaningful difference. Cross country 25 mile run, assuming identical traffic for both cars then the 335dx might get you there a few seconds sooner, but it's how you feel at the end of the journey - which do you actually enjoy driving more? Plus how often are you going to be sat in either car frantically chasing the other across country and then lamenting afterwards "I wish I'd bought that one"?

[KTE]

Avoid making a decision on unlikely situations, does it snow regularly where you are? Torrential rain?

435d isn’t immune to the above either, so winter tyres will be needed, but when it’s only slightly damp I would be willing you say you can push on easier, especially if you don’t have much experience driving ‘performance’ cars.

[Quakered]

Simple really, do you want a BMW or a diesel disguised as a BMW?

[fuzzybunny]

My 435d is great with effortless torque and really quick even with the extra weight of the convertible hard top, the xdrive just hugs the bends even in the wet. Engine is very quiet considering its a diesel and the 6 pots make it very smooth. Standard xdrive suspension is fine normally but accelerate hard down a country road and it will feel bouncy with light steering but it absorbs the bumps fine, none of that bone rattling. Living in the country though it works for me, higher ride height on the xdrive (15mm) as well so looks less sporty but improves ground clearance.