^ what he said.
And even then, haven't met many at 150 hours that would make very good teachers - still a lot to learn.
I have met pilots with thousands of hours and multiple type ratings that couldn't teach nothing........
I'm seriously considering building a Challenger II aircraft, I may move to the sport pilot area.
They are good aircraft, but if your goal is to give dual instruction, just be sure you understand that you cannot give paid flight instruction in an Experimental that you are providing (except in certain cases where you get a waiver to provide type-specific transitional training, not general dual instruction). You would need to purchase a certified LSA aircraft if you're planning to charge others for instruction.
Just a side note on choosing CFI (61 Subpart H) vs. CFI (61 Subpart K):
If you do go with the CFI with Sport Pilot rating (61 Subpart K), and you train students through their sport pilot certificate, and those student(s) want to get higher-level certificates (ex. private pilot, comm. etc), none of the training you gave them will count towards satisfying the experience requirements of those higher-level pilot certificates.
Reference: http://www.faa.gov/about/office_org/headquarters_offices/agc/pol_adjudication/agc200/interpretations/data/interps/2009/Kern INK.pdf
Depending on the area/school/market as others have mentioned this might not be a big deal for you, but its a good thing to keep in mind.
I know that to give flight instruction the aircraft has to be an S-LSA. The Challenger II needs to be registered as E-LSA or E-AB. I'm not getting the flight instructor certificate for the money I'm doing just to get another rating in the pocket............
How many hours to get the CFI?? I have not flown a complex airplane in a long time. Would you consider 10-15 hours to finish a reasonable estimate???