i bought a new AB14 full ignition amp from a trusted Jag supplier a year ago - aftermarket made in UK for only $176. They still offer them at that price.
My old one had compromising wiring, and the guts inside looked quite corroded.
It seems to be decent quality, although I replaced the unknown HEI module inside with GM. Also, the big zener diode of the 80s is not in there, I think it has a more modern two little diodes in parallel, as Kirby points out in a thread from 2016?
So you don’t need to pay $300-400 anymore…
BTW, the interesting thread about the big zener diode not there anymore here: