Some wiring questions!

[jarrett at rpa.net (Jim Jarrett)]

1) I am installing a 3-gauge setup in my Scirocco.  I have an oil  
pressure gauge.  Which line is switched power, and which goes to the  
sender?  On the back of the gauge there are three tabs.  One is  
labeled with an inverted "T"; the wires running off of it are brown,  
so that's ground.  The other two are "+" and "G".

2)This is an '88 with *gasp* the stock radio still.  (That's going  
away).

On the power connector, there is a thin black wire that runs up the  
antenna.  I am installing an amplifier.  Do I need to connect this  
wire to anything on the wiring harness that plugs into the back of  
the radio?

Doesn't the "powered antenna" line off most after-market radios  
control the raising and lowering of the antenna vs. actually  
supplying power to the antenna itself?