Hi,
I choose 330e because of iPerformance (PHEV) at least new technology (I dare to try even some people say wait for it to mature first) which perfectly suit for city drive with hybrid, somemore is plug-in which is different to others Japan hybrid car. The combination of eDrive (3 selection) + Eco pro, Comfort, Sport, Sport+. It is really fun to drive. This car is loaded more specs among the 3 series which we really like. Sunroof, Headup display. Of course, no M sport.
In terms of performance, the statistic shown that 330e faster than 520i because of the combination of power output even the weight is heavier (hybrid battery). In reality, perhaps you won't feel much different. So it is no concern for you.
Spaces, 520i is your choice. The E-segment is larger. Personally, I didn't get complain from my family (2 adults) who sit at the back

Again, the drawback of hybrid battery will occupy the boot space, therefore smaller. If you are travelling more often with luggages then 520i.
Price correction, 330e should be RM248k. If you came across RM238k let me know.
On more condition make your decision better, if you are not convenient to charge your car daily, then 520i. I am not saying the 330e must charge from power outlet. It can be charged when driving, however you might not utilise the electric power in a more efficiency way.