Removing the front bumper isn't rocket science.
I can probably remove and put it back in less than 20 minutes. It helps with two people, but isn't completely neccessary. There are only 6 bolts on the front, 4 bolts on the top near the radiator and another pair of nuts to remove under the front wheel well. The service manual is missing some of the bolt location, but a search on prime will easily tell you where it's at.
Just protect the front fenders with blue painters tape when you go to put the bumper back on.
This is a good opportunity to put the NSX-R bar on also, if you haven't gotten them yet. You don't have to remove the bumper for this, but it's easier if the bumper is already off.
Try this store, Industrial Metal Supply (IMS). They have a warehouse in Phoenix also. They have a lot of different metals you can use for a grille. They have some nice honeycomb patterns that are similar to the Lambo front grilles.
http://www.industrialmetalsupply.com/location/phoenix.htm
Take a vacation here to San Diego in the NSX. I'll do for you in my garage.