mikbik, actually we don't have problems with the 30 weight oil kahit pang araw araw dito. we've even taken a couple of the cars with the 30 viscosity oil to the track and run them over numerous laps without problems.

if the oil you use is thermally stable and does not absorb a lot of water then you will have no problem using it every day kahit na extended drain intervals of 10k kms or 1 year. royal purple is made of group 4 base stocks and if any oil can take the abuse of stop and go traffic, the occasional hataw and even fun runs and track days then this is it. most other synthetic oils in the market are made from only group 3 base stocks which is why they are not as stable as royal purple.

17M, the contact number is in my sig, the address and directions to the shop are in my website (in my sig), and yup we do all of that work