Joe
The cross over exhaust takes cylinders 2 and 3 from each side and crosses over to the pipe at the other. By doing this the firing order pulses once down the left pipe and once down the right
I may be told differently but the other makes of engines should sould the same as the Ford in this configuration. Yes header lingths and tuning come into the equation but you know what I mean.
http://www.gt40enthusiastsclub.com/ will take ou to a club site and yes there is a meeting in the South West.
I would presume MDA would make you welcome - anyone interested enough to find them is at least doing their homework!
Hell when I arrived in the UK I drove a Fiat Panda and later a Punto - don't knock your wheels - learn to drive safely and keep your dream of ownership - it may come true!
Ian