Sourcing Parts in the PI for other than local cars

Coming from Southern California where I grew up with deep performance car influences, my slower years here in the PI still result in urges for performance.  Although I prefer US version GM & Toyota brands, the engine & drivetrain selections here in the PI are very different than most other non-asian countries.  To this end, I think it would be nice to hear from others on how they source parts for a make/model that is not manufactured/assembled in the Philippines. 

Example:  I have recently purchased an Opel Omega and the correct "Tune up" parts are hard to source here.  When I checked for the same upgraded spark plugs in England, the price was well above a 10X factor increase.  When I checked on Mobil 1 or other Synthetic oils in the NCR, it was 20-30% more in NCR.  My solution has been to order "Cadillac Catera" parts from US sources, ship them to the family in California and then ship to the PI.  This is the route I took to get the proper parts for a German GM Opel (rebadged in the US as the Catera).

There must be better alternatives (i.e., order from Australia, Japan or a hidden local source ?).  Part ordering can be a tricky process and one must always be reminded of the "right-side" vs "left-side" drive differences for some body and suspension parts… etc.  Lastly, I am not trying to engage in a debate on which brand (i.e., GM, Ford, Toyota, VW etc.) is better or worse.  We each make our buy decisions based on very individual tastes and family needs/wants.  I am just trying to obtain/share proven part sourcing options without judgement or raised levels of scorn toward any car owner for his/her brand/model selection.