For what it's worth, Tore Bergvill (owner/manufacturer of the kits in the link) has a great reputation over at Rennlist.
Extremely helpful with diagnosing electrical issues/anomalies. I'm planning on sending the ASK amplifier from mom's 987 to him to be repaired as to not suffer the same failure type again.
Check out the testing equipment he's created for specific Porsche parts (
https://www.bergvillfx.com/index.php/services.html). He's thorough.