Combine the olive oil, balsamic vinegar, brown sugar, garlic, cinnamon, rosemary, salt and pepper and sriracha (if using) and mix well. Pour into a resealable plastic bag or shallow dish large enough to hold the tenderloins.
Trim the silver skin and any excess fat from the tenderloins and place them in the marinade. Turn to coat and seal the bag or cover the dish. Refrigerate for 8-12 hours, turning occasionally.
About 30-45 minutes before grilling, light your grill and heat to medium.
Remove the tenderloins from the marinade, reserving the marinade.
Place the reserved marinade in a small saucepan and bring to a boil. Reduce heat and simmer while tenderloins are grilling.
If you are grilling the apples and or peaches, cut the peaches in half and remove the pit. Core and thickly slice the apples into rings and toss with lemon juice.
Place the tenderloins on the grill grates and close the lid. Turn the tenderloins every 6-7 minutes.
When the tenderloins have cooked for about 10 minutes add the peaches and apples to the grill. Cook, turning every 5 minutes until grill marks appear and they are tender.
Remove the tenderloins from the grill when the internal temperature reaches 140-145°. Place on a cutting board and let rest for 10 minutes before slicing.
Remove the apples and peaches from the grill. Slice the peaches into wedges. Place the fruit onto the platter with the sliced pork tenderloins and drizzle with the reserved marinade to serve.