I got my heater with the relay kit at KTA services. My only beef is
that the magnet on the relay has come apart and has needed to be
epoxied once. Otherwise, it's a slick operation.
As far as installation, either put it in the empty air inlet duct
located above the passenger's legs, which will save you lots of
installation time-- or follow your Helm manual closely. Lots of wires
behind the dash-- they'll all go back together just fine, but it will
make you a bit nervous until the last bolt is tightened and it's all
done...
peace,