there have been numerous posts on volvo forums about swapping an auto for a manual (as volvo did not offer manuals for their turbos, but did offer them for their lower output n/a engines....which, as turbo by design, works much better with manual in terms of matching speed with revs, anyway)...most agree it is simply too troublesome, time consuming, and costly to do so...it'd probably be easier to go north to canada and buy a manual turbo (which does not exist in us, at least for volvo) than swapping....
u'd have to remove the auto trans computer, rework the engine computer, add a clutch pedal (unless u go sequential clutchless manual)...etc., etc., no doubt, that's one of the reason why brabus charges $11000....take away half the normal expensive benz aftermarket company price, and u'd still run up to $5000...