Got a Modded new style Emaxx coming in need advise on gearing and batteries

[suicideneil]

You were lied to, an MT weighs more than a 1/8 buggy in most cases, especially if its loaded with aftermarket parts (metal im guessing) and has typical MT sized tires, so you will be needing some good batteries.

1. http://www.scriptasylum.com/rc_speed/_top_speed.html to find your gearing
2. not sure, refer to the main traxxas site to find dimensions for the battery trays.
3. yes.
4. Revo spurs will fit the 3905 slipper, but refer to the calc to determine gearing on 4s lipo and ~2000kv motor.

30 mins will probably need either large capacity true rc/ maxamps cells (8000mah?), or something like 25c enerland based cells (5000mah?).