Hi Tony!
Where have you been, by the way? Haven't heard much about your custom installation.
I'm working on a web site to explain all! It's been a long and interesting experience, and basically now the car is just awaiting the return of it's dashboard. (It was sent away to be retrimmed and should've been back from my supplier in February... don't get me started!!).
Anyway... In the meantime we figured out some interesting solutions: fitting a 6-channel Mac in the boot of an MGB, with room left for spare wheel, tool kit and shopping! Inside, every panel has been Dynamat-ed, and the audio wiring has all been beautifully and painstakingly fiitted underneath the car, shrouded in heatproof exhaust wrap... try getting that done at your local audio install place.
It's all taken waaaaay longer than I'd hoped, but at least it's all been done right... I'm praying that it's gonna be ready for mid-May 'cos the annual London to Brighton MG run lands on my birthday this year, and that would be a very cool way to spend the day - blasting through the countryside with the top down and the empeg up!
Sally