Preheat oven to 400 degrees F.
Combine garlic powder, salt, pepper, chili powder and paprika. Using clean hands, rub spice mixture over tenderloins to coat well.
Heat oil in a large pan over medium high heat, and add tenderloins to the pan to brown on all sides (approximately 5-6 minutes total)
While browning the pork, combine brown sugar, syrup and butter in a small saucepan. Cook on low, stirring constantly, for approximately three minutes or until smooth.
If using an oven safe skillet, leave tenderloins in pan and coat with approximately half of the glaze mixture. If not using an oven safe skillet, transfer tenderloins to a 9x13 glass baking dish that has been sprayed with non-stick cooking spray, then cover with half of the glaze mixture.
Cover and bake for approximately 18-20 minutes or until the internal temperature reaches 135 degrees. Remove from oven, remove foil and top with remaining glaze. Return to oven and bake for an additional 5-10 minutes or until the internal temperature reaches 140-145 degrees. Pork will continue to cook, due to carry over cooking, one removed from the oven
Remove from oven and allow to rest for ten minutes.