I think it's fine to get it now.
I have a similar mod to you: SR 70mm tb/plenum combo, Steeda CAI, I just got Pypes O/R H-pipe, and am looking to get them put on in the next month when I get my tuner.
I fully expect to feel a gain (nothing unrealistic) but with my set up I would expect be making somewhere in the neighborhood of about 285-300 flywheel HP, and I think a lot of that will come once the tune combines with what I have already done.
I don't think your car will run poorly without it, but you seem to be at the right point to add it (maybe add a larger plenum also).
Also will be nice for you if you plan on still doing more (gear and tire changes) or other bolts on's up to a point.
If you stick around the site for awhile, you will actually gain a discount with some of the suppliers to help you save a few bucks on the goodies.