TinyRC.com - ZZ Nitrous v. Bit 3.8

Alrighty, I haven't posted here in about 3 years, so here it goes. I've heard people comment about the top-end RadioShack motors (NOS/nitrous/whatever), saying that they have a relatively low acceleration rate. I own one of these motors, but I have nothing to compare it against to prove this theory. I've also heard that the Bit Char-G 3.8 motor, apart from having 4k extra RPM, has a much better acceleration rate, and of course a bit faster due to the higher RPM's. With that being said, here is my current setup along with a few questions:

ZZ SE:
- "NOS" 34k RPM motor
- "Turbo" Red gear set
- "Performance" tires (V-tread)
- "Initial D" Toyota Levin body

Would going back to the stock blue gears or the green ones improve acceleration, solving the sluggish-ness of the "NOS" motor?

Is the Bit Char-G 3.8 motor worth ordering from this website, or could I get it at a particular store to save shipping money, etc?

What parts from other companies will fit a ZZ SE?

Would I need to acquire a new set of gears to make this 3.8 motor perform at it's best?

What other upgrades would you reccomend for a nearly-stock SE?

Any advice or recommendations are appreciated.