That's great! I use Shell Helix HX-5 the one available in yellow cane, also used Havoline but can't feel any difference.
Now you're asking for Guard oil, I have been using it for more than an year BUT I use it for a Charade which is in very bad shape, SACH POCHO TO YEH TOTAL BEY-CAR DISPOSABLE CAR HAI And you've recently rebuild your engine so I recommend you NOT to use Guard for next 3 oil changes (7000-8000 kilometers). Someone told me Zic is expensive but not that good.
And one more thing, always buy your engine oil either from filling stations (PSO, Caltex, Shell) or a good well known lubricant store. Counterfeit oils (جعلی تیل) are very common in Lahore and Karachi and they can ruin your engine in no time!