Any auto electrician / car audio joint does it

But seriously dude, it is so dead easy!
You could have it done in 20 minutes at most if you did it yourself.
If you have an RX65, just go to trickys, get some phone cable, crimp a phone plug on one end, expose the other wires at the other, figure out the positive wire, pull off your steering column, look on the opposite side to where you put your key in the ignition, you will see 2 big blobs of solder and some black cables, multimeter the cable with your ignition on till you find +12 volts, add your radar wire to that particular solder and negative earth the negative wire off of the screw holding your ignition in place.

You could have it done in 5 minutes if you tried hard enough.