what is the part number or mounting bracket called that attaches the bumper to the fender with the two bolts behind the wheel well liner?

 

These are the p/n's from my '08 Coupe sport bumper:

(L) 62059-JL00A, and
(R) 62058-JL00A

I paid $15.83 each (direct from Japan). Install was roughly 15-20min. each side.

I would imagine the brackets are the same for all G's but I can't say for certain. However, go to parts.infinitiusa.com, enter your cars VIN, then enter the p/n. Their catalog will tell you if it will fit your car and, if not, provide the correct p/n. You won't have to buy from there- just confirm fitment.

 

The coupe and sedan use different parts. Plus the ones you mentioned are the ones that go in the engine compartment.

 

For the coupe it's called the "front Bumper/Fascia to fender Bracket". But you can try the junkyard or just ask any reputable body shop and they should be able to give you the part number.