I'm going to be mounting a nitrous bottle here..and was wondering if it's safe to mount the brackets here...because I'll have to drill a few holes...

 

Just dont hit the driveshaft and i dont see why it's not a good spot. Ive seen nitrous bottles hooked up there on third gens. If you're worried about it, jack up the car and looks under it. See if anything is in the way.

 

Then again, they might have been "flat bolt head's" on the bottom... or just a short screw.

 

Your emergency brake cable also runs in that area. Just a thought!!!!!!!!!!

 

im pretty sure they fuel lines run somewhere near there too.

If it were me, i would jack up the car, pull out the driveshaft (its only 4 bolts) And then have a buddy under the car to make sure your not drilling through anything important.

 

...Besides all that - It looks retarted there. Yes, its easy access but for the love of all that is good - Ditch the spare tire and mount it there... No drilling thru complicated areas and you get to have the sleeper look still. Besides, if you get pulled over, less to explain.

 

aside of hitting the driveshaft or possibly nicking the e brake cable (things that should easily be avoided) the only thing i can think of is that you may want to double check where the wiring for your fuel pump runs(inside of the car), only because when i pulled the carpet to gut my car those wires were pretty much loose around there so i believe their location could change from car to car. Im 99.9% sure that they would not be there though, so if i were you, i would dis. the battery and just drill. And as far as fuel lines, those do not run anywhere near there under the car unless yours have been changed from their stock locations.