Go to the junkyard and look at Volvo's and other Bosch injection cars. They have the 3-terminal plug that fits on the TPS, but they are completely insulated and look really nice and pretty. Cut it off, solder & heat-shrink it to your existing wiring harness.
(edit) - Just FYI I've actually done this, unfortunately I don't know which exact year or model, but I am 100% sure I have a nice clean insulated OEM plug from another vehicle on my L28E's TPS.