In order to have a vacuum supply to purge the carbon canister we had a piece of fuel rail section about 10 cm long drilled and tapped along the top to accept four hose adapters. The A T Power throttle bodies are supplied with blank ending bosses which can be drilled through to the chamber for just this purpose. The hoses were then connected up and this new balance chamber suspended from an engine bay cross member beneath the inlet trumpets. Finally, the ends of the rail section were plugged and tapped to fit a takeoff for the adjacently mounted MAP sensor at one end, with the other leading to the solenoid valve scavenged from the original Focus engine. I managed to modifiy (saw up!) the original bracket which has a nice fitted rubber collar for the valve, and by bolting this to extrusions which used to hold the water block at the rear of the engine we've been left with a very neat install. By my standards anyway......
As a note, when the engine tuning started, Paul noticed a pressure oscilation in the balance chamber which was throwing off the sensor reading. We presume this is either resonance or due to a steal between a pair of TB chambers. Either way we were unable to eliminate it so in the end the MAP sensor was isolated from the vacuum balance chamber and now supplies atmospheric info. Paul was able to work around this in the tuning process and it hasn't affected us at all - as witnessed by the IM 240 pass recently. We may try a different design of chamber later on but, as the saying goes, if it ain't broke have a beer instead
We spent a while looking at options and designs of airbox. The main requirement was to fit under the bonnet without too much metal work so that we could mount the filter internally. This should mean a reasonably quite induction noise which will be essential to pass the noise emmissions test. We have been a bit worried about this element as I used to have a modified Peugeot 205 GTI which ran throttle bodies and sounded a bit like a canal barge trying to achieve earth orbit, even at idle. Fortunately A T Power (who supplied the throttle bodies) had a link to a company called Reverie, which makes among other things carbon airboxes in a multitude of designs. After much measuring up and head scratching we settled on a model that fits the bill, the Zolder 65 with shallow baseplate option. 
The next problem was mounting it - carbon fiber is not easy to cut, makes tonnes of very nasty dust and obviously is not cheap to replace if you get happy with the power tools. So we cut a template out of mdf wood to match the intakes and clamped it to the backplate. It was then straightforward to use a hole saw to make the apertures in the correct place and all was calm in the garage. It looks, although we are proud parents, bloody good....! We had to file down the quick release tabs so that they didn't stick up too far and then it was on to the next task - cutting the hole in the already painted bonnet. Eek!
