BMW 3 series is an entry-luxury sedan which has very good dynamics and BMW X1 is an entry-level SUV which has a good hold on road. So, if you are looking for a good comfort and performance BMW 3 series is a good option and if you are looking economical and driving pleasure than X1 is a good option. Moreover, for detailed comparison click on link
For this, we would suggest you walk into the nearest service centres. You can click on the following link to see the details of the nearest service centres and selecting your city accordingly - Service centre. Moreover, for an idea of the prices of the spare parts, you may follow the below link - Spare Parts.