Take off the trans pan and look at the magnet. Is there a lot of gray crap and/or metal shavings on it? If so, you may have a problem. If not, your lucky, but get that fluid changed NOW!
It should be worth the time, and it is not hard at all. Do you know how to use a drill? How about using snap rings? Its simple stuff. Unless you plan on making HUGE amounts of hp and torque, the j-mod for you will consist of drilling the separator plate, upgrading the pistons, instaling a trans cooler, and filling it up with mercon v. All you have to do is read a-trains how-to articles (the two right below trans 101) several times over, and you should get a good understanding of whats going on.
For the sake of your wallet and your trans, don't order the transgo kit. That inferior pos should be left to ignorrent 'stang owners (not all, just the ignorrent ones!)
Get the 24000 gvw rating b&m supercooler from summit. Comes with (almost) everything needed, just need another 5ft of 11/32 hose
It is better then ok. It should be the only fluid used in you trans, no more merc 3 for you!
You don't NEED any special calibration, but a dennis chip is a nice addition
You could drive it wherever the hell you want after the fluid is in. I don't get the point of this question.