make sure it is in neutral, could be in 3rd, that is all i can think of

i you can not find them you can always use zipties with eyelets and can get them at home depot

check for a short, and check your ground wire if you reversed polarity in the system

mtx or JL evven lower end models are better than something you will find on ebay

red electrical tape, cheap and looks alot better than paint will

could it be the wire sizing being too small now that you have more power wanting to go to the tail lights or your ground wire you used is too small for it to return?

i have a 93 tsi as well, mine also has this issue, i am sure it is the tumblers worn from x amount of times it was used, needs a new lock on driverside

2 F A L fans did wonders on my gt4, i am using them again on the tsi they worked that good

had this issue with my car, the secuity key has contacts deteriorating and would make the noise, battery was new, terminals all cleaned, grounds all taken off and sanded to make sure, and after soldering it car starts great everytime

could be a lose or damaged connection in the fuse block or a worn fusable link if all else fails

injectors dirty? bad spray pattern could cause issue but you would lose power and should get an engine light