Well... my choice is Wheels Asia!
Its comprehensive coverage of latest automobile news,
exclusive car reviews and annual car driveaways; at
an affordable price of $3 per issue are their strengths.
They even publish an annual issue of Wheels Asia Buyers' Guide
at $10 that features available cars from all authorised
dealers in Singapore.. their specs and brief review of
them.
I have been buying the magazine every month for 8
years since November 2000.
You should be able to get them pretty easily at
7-Eleven, petrol kiosks and all major newsstands.