On your grille fitment, I've got to wonder if you could gently bring the side pieces into place to bolt them down but not tight, then bring the center section into place and get the bolts installed, followed by carefully snugging everything down if over time the pieces won't take a set in their mated positions and slowly relax into position. I'd be tempted to give it a try, maybe even using a heat gun on the pieces that seem stressed, leaving them overnight or out in the sun for a few hours and coming back to coerce them into place. No guarantees, but I think I'd give it a shot. What choices do you have other than trying to convince the parts to fit?