First of all, congratulations on getting your GD up and running.
Secondly, did they tell you the extent of damage that was caused to the engine? Were any engine components replaced? What exactly was done to rectify the problem? (I doubt they'd have given you any details, Suzuki mechanics are so mean!)
I am using Kixx 4T Ultra in my GD since last September and I am having a pretty good experience with it so far. 1L bottle costs somewhere around PKR. 430 and I usually take it to at least 1,500 km before draining it out.