Where should I put these fans, I don't see any way to mount something in the 5.25" bay, and the air flow from the PSU compartment seems limited, is the top as an inlet worth while?
Antec removed the fan mounting in the hard drive bay when refreshed the P182 into the first release of the P183, so the only place is behind the cage (which you should remove, if you don't use it).
In the original P183 the top exhaust is to be avoided due to vibrations and interference to the fan turbulent flow, unless you wanted to cut the original fan grille (it's not an easy task in that cramped space).
Frankly I don't know whether or not they corrected this annoyance in the current P183V3, but neither I know which P183 you own.
Personally at first glance I'd try orienting the Macho fan parallel to that grille (without any case fan there), favoring the natural hot air convection through it (sort of chimney effect).
At any rate, noise-wise the main issue I see is that you don't drive the fans by a convenient BIOS/software solution.
As I don't know which motherboard you actually operate, if I were you I would pick a PWM splitter (Akasa Flexa, Gelid, Swiftech) and I would drive all the fans (cpu, back exhaust, front intake) through the mobo CPU fan header: but in order to do so, you would need to buy PWM fans, as the Slipstream PWM, and not the otherwise excellent Slipstream M.
As unrequested suggests, I think you don't need a Macho to cool an X6 1055T (I use a Big Shuriken 2 to cool an identical CPU), and if I were you I would look to the Scythe line-up, rather than to the TR one, as Scythes are usually cheaper and with far better stock fans.
Anyway, if you want to stick with TR, as I don't like very much the TR-14X/15X fans, I would probably look at the Macho 120, not the Macho Rev. A, but then I would need another Slipstream PWM fan to put on it (as the TR 120mm fan is actually annoying).