it's worth speaking to Ben Afford as he can make manifolds and plenum chambers for a custom supercharger or turbocharger setup.
Peter Feltham has a custom turbo setup, also with
The modified mini car club of south australia (hotbricks S.A.)
www.hotbricks.org.au for more info.
both of these setups compress the air after it's mixed by the carb thereby avoiding the need to have a special sealed carburettor.. but you'll need to get a sealed turbo or s/c which is easier as you get the seals installed when overhauling you're second hand turbo.
No blow off valves or intercoolers... But suck through's are really simple and cheap and you can mount the carburettor anywhere you want to get it out of the way.