I am new

I got the louvers at cal-mustang.com, but I think that cjponyparts.com has them.

No, not a purge button (I had the car for a year and did not know what it was) it is for the alarm (it comes on when the alarm is on) I get ask that a lot.
 
I will get you some better pics of the shifter (it's not much of a shifter) the roush shifter is a handle, shift knob and a boot thats all, you put the roush handle on stock shifter, not worth $250.00, but looks good, the roush handle will fit the hurst shifter and others (and it will look the same). I am going to try and put it on a pro-5.0 shifter.
 
as long as it has stock mounting holes on the handle, it will work. those stripes do look pretty darn good. You should get some lowering springs....