Insha Allah. That is really good. Yes it has wifi, I installed each and every thing on it using a Wifi connection. 3G enabled internet usb will be plug-n-play, no additional software would be required. No, i haven't but i know someone who tried it (Evo Usb).
Yar it all depends on your budget, if you running on a tight budget simply get the tyres replaced with (Yokohama/Michelin;195-65/R15) you will have to pay 13K-14K. Try not to go beyond 205 width-wise (my advice, rest its on you)
Now if you have moderate budget, go for the alloys as well (But try to buy branded ones), 15" or 16" ( your personal preference and budget)
If you are going for bodykit, the complete will look good, This time the shape is a bit different so only getting side skirts won't do the job properly. As long as its a good shop, paint matching won't be an issue (bronze mica is not a new colour, if i am not wrong, i have seen couple of 10 Gen corollas having this color).
Now if you are confused between alloys and bodykit, Go For Alloys. Hahah..., I hope this will be some help !!