Guessing this is for your 2006 GP (try including that when asking model-specific questions)...
While I'm sure there's a quality gap to aftermarket housings, you should have a bit of adjustment on there to mess with (pretty sure I have eBay ones on my '06, as well). Just nose up to within ~5-10ft of a wall/garage door on a flat surface, and watch the slow change in focal point of the light as you turn the adjusters. Someone will have a way more fancy approach, or exacting numbers, but it's not super critical, as long as they point the right direction in the end.
While I'm sure there's a quality gap to aftermarket housings, you should have a bit of adjustment on there to mess with (pretty sure I have eBay ones on my '06, as well). Just nose up to within ~5-10ft of a wall/garage door on a flat surface, and watch the slow change in focal point of the light as you turn the adjusters. Someone will have a way more fancy approach, or exacting numbers, but it's not super critical, as long as they point the right direction in the end.
