I have driven this vehicle many times  and  ithe following
things noticed  in the new facelift  WagonR VXi   against Santro Xing
XO are as follows
1.  Electric adjustable ORVMs  (Santro has only Internally adjustable ORVMs)
2.  Keyless entry (santro has only central locking)
3.  Fog lapms (most probalu been removed in santro top end)
- wheel caps  (for santro it comes only half) 
- WagonR has only front power windows (santro has front and rear) 
- WagonRs Interiorss center console and steering has silver finsih 
(awkardly designed steering in santro and noo silver finsih)
- rear seats of WagonR narrow like a bench(santros rear seat comfort is good) 
- Ride quality and suspension better in wagonR(Santros ride bot bumpy at the rear) 
- WagonR has 16valves DOHC engine and santro has 12valve SOHC engine 
- WagonR has electronic power steering which is super cool compared to santros hydraulic one. 
11 . Milage of WagonR is around 13-14 in city and 16-18 in highway
whereas santros is 12-13 in city and  around 15-16 in highwway.
12 .  WagonR has  facelift where as hyundai people are trying to bring
thier facelift santro by the end of the year or early next year and if
u buy santro now  your resale will effect.
soo these were the things  and features and facts  of both WagonR VXi
and Santro Xing Erlx XO.hope ythis review helps u find ur dream vehcile.