Well congrats on the G purchase! It's a great car, and frankly I'm glad to see a "cool" mom that went with the coupe instead of the sedan! Anyway, do a search for rims and see what you come up with. I like the ones in this thread:
zerothread/172011
Now, the video system may be tricky...our headrests are "Active" meaning in an accident, they will move forward (to prevent whiplash). Your best bet is to find a good car stereo place, not best buy or circuit city, and have them do a professional install. Try hi-fi buys or a reputable installer in your area. It will not be cheap, as you may have to upgrade the head-deck. Another option available is to get a portable player for the kids with headphones...