Thank you both for all of the information. I'm still trying to decide a bit. I think I've ruled out the bbs01b just because I think the 02 does about the same and like you mentioned it has a little more meat inside. I'm starting to lean towards the hd even though its 48 & 52v I've read that I can temporarily set it for a lvc of 38 so I might be able to "rig" my batteries up for now and then get a bigger one later on. I probably wouldn't be able to use it very far like that but it would at least get the motor part and all the wiring, etc. done. Is there any reason to not buy this stuff on Amazon? That's where I am finding the cheapest prices so far. I can get the bbshd without a battery and a DP C18 Display for $690, and possibly a 5% discount also. I don't need the extra power if the BBSHD but I might swap this to a nicer bike down the road and don't want to have any regrets.

As far as sprockets I was leaning towards the 42t also but wonder if I should do 44 or 46 but I do want to be able to pedal along with the motor and not just be on only electric. My MTB has a 42t front gear and the smallest rear is 14t. I've found that going down hills its geared too low to pedal and end up coasting until I level out some. My road bike has 50 in the front and 11 in the rear. I was thinking somewhere in between the two but maybe the 42 tooth is the best?

So skip the supplied brake levers and go with a brake sensor & also a gear cut out sensor?