Go for the Catalytic Convertor removal.. I just got it removed yesterday!! now lets see in coming days that what milleage does it give,, Removing the CAT was my last resort...
Now i,ve done all the things
Valve Clearance Adjusted
Throttle Body Service
Air Filter
Drive with a lite foot and do not go beyond 70 - 80Kms even if road is empty
Cat Removal..
If now again if i get bad mileage!! I,ll just live with it !! My current mileage = 12.25 Km/l.. I drive 60% with A/C and 40% without A/C.. I doubt if i drive with 100% A/C it will give me 9Km/l...