Durability is quite good. Before this 2015 Alto i owned a 2006 Alto which i bought in 2012 and sold it in 2016 after driving it to 126,000km. At the time of import it was 36,000. In all those ears one leaked shock was the only thing i spent money on other than basic oil changes and filters etc.
Basically X is top of the line variant.
S variant are mid-tier which will have powered mirrors but dont search for ads that say Alto S or Alto L since idher ki un parh showroom wali awam Fx ko bhi Turbo Fortuner likh detay hain. Just see the pics of the car and you'll know if its base variant or not.
VP, F , L are base models and i think Vp is the lowest one even without power windows.
If you are getting them in 11-11.50 thats really great just to verify its auction sheet and buy a genuine one even if exceeds your limit. 50k bacha k accidental car lenay se jab tak gaari rakhi tang rahain gay aap