For this, we would suggest you walk into the nearest authorized dealership as they will be the better people to assist you. You can click on the following link to see the details of the nearest dealership and selecting your city accordingly - Car Showrooms.
The claimed top speed of S Presso is 140 Kmph. Comparing the two variants VXI Opt and VXI Plus, here you may find the difference on the basis of available features. For the detailed comparison, follow the below link - Compare.
FWD means that the power from the engine is delivered to the front wheels of your vehicle. With FWD, the front wheels are pulling the car and The rear wheels don't receive any power on their own. Moreover, Maruti S-Presso is a FWD car.