personally not seen plug in on a t2, mind mine was a 96 and spliced..
as it my '00 trol.
with splicing go to trouble of making connections up in body not as
could be tempted behind bumper for those clusters as sooner or
later mud and damp will interefere.
I have added a second batteyr and auxilliary circuits to some vehicles but to be honest never a 12s socket, personaly i dont see the point in them, just use more fuel when you're towing for no real gain. Even when i have a vehicle with a 12s socket i dont use it. So my advice would be not to bother.