@Rakesh:
Sirji that is one of the toughest question I have ever faced. Alto is a steady steed which is already well proven too. Good FE, low maintenance and a very competent A.S.S.
I have driven an Alto LXi for around a complete week back in 2012. In fact even took the Alto on a long drive too (highway + hills). Of course the vehicle feels under powered at times and really needs some throttle inputs to keep the vehicle moving. Still on the highways I managed to get 20+ kpl FE on the highway doing 70-90 kph for whole time.
Kwid may look promising (more promising) but as an upgrade from Alto, IMO it won't fit. I remember driving a K10 AMT that costs around 4.2 - 4.3 lac OTR. Alto K10 now gets a better interior, a better all round visibility (Kwid has thicker pillars and a rising window line), internally adjustable ORVMs, 1000 cc potent engine and above all is an auto tranny. I really doubt if Kwid can match this one at the price.
A better upgrade from Alto for 25-50% budget rise IMO can be a K10 VXi or K10 VXi AMT or a Celerio. Kwid can be an option of Alto but not of K10, rest a TD will confirm.