I would recommend not installing them until you install the MAF. You'd just be throwing fuel economy down the drain..not to mention the idle problems you'd come across. Just hold off on it and do maf/injectors/nitrous all at once....and get a tune on it ASAP.
EDIT: I re-read a bit...as long as the maf and injectors are installed and tuned correctly....you shouldn't be running rich at all. It's all in the tune.