I think that is about the only place you have room to fit an SC on the xfire, unless you junk the inlet plenum and fit it between the V like the SRT. Something that has just occurred to me is whether there are any issues with running higher that atmospheric pressure on the plenum; the internal inlet tract switchover flaps/valves may not be designed to function with reversed pressure differential. I'm sure it will be OK but you never know. There's also the myriad of other actuators that are vacuum driven to consider. From the calcs I did a while ago for the Rotrex I don't think anything more than 3-5 PSI is practical anyway with 10:1 CR, so it may not be a problem. I'm hopefully tearing the plenum and heads down this weekend so I'll let you know what I find.