I am driving Cuore A/T these days, and its faster than M/T from 50kmph - 100kmph due to different gear ratios. Yes its 3 speed A/T but that doest mean it cannt go 100+. I have personally driven it at 120 and without any issue. The correct engine size is 826cc and not 850cc. Having one gear less doesnt mean the engine generates less power or top speed of the car is affected. Altis 1.8 Cruisetronic is 4 speed and Altis 1.8 M/T is 5 speed. Its all about gear ratios and A/T cars usually have different gear ratios and generally all A/T cars are faster in 50kmph-100kmph.
We have Cuore A/T with us since Dec 2008; its been in my wife' use and we never faced any issue in its tramission or anything else. Lately I am using it almost full time and I have noted that only its doors/mirror machines have losen that sound on bumpy road, and this is also norm in smaller cars like Mehran, Cuore, Alto and even Cultus.
A personal note; ours is Ecomatic; but its always been on petrol...earlier it was used so sparingly by my wife (short trips to nearby markets) and when I started driving it lately I found driving Cuore A/T with petrol is so much fun comparing to other 800-1000cc local hatchbacks and ever since I am driving it on petrol and its economical (if you dont mind paying a bit more than CNG for driving fun)