ok i have done every one of them mods.. teh dual motor technicalyy can get u more speed because u can use non standard gears to get HUGE ratios
running two 3.8 is much better than 4.2s they dont have enought torque.
li-po is easy pretty much empty out the chassis and stick them in and fit everthing else in around them.
tyres i find depends on what ur running if its perfectly flat lino or sumthing then get as soft as u can up back and a medium on frounts (will help stop it flipping)
as for fets maybe try getting a biff they are arwsomly easy to install and get great performance
few thing i suggest put in bearings at rear and frount not hard to do.. just look around on a german site for a tute and also if ur game u can put bearings up frount which is abit harder.. also get some AFX slot car springs and get suspention on the frount this car ur building will be nuts on perfectly flat surfaces but cornering will be hell so get springs to help that… lower ur body tons to get CG down low.. put 2 or 3 springs on the steering arm to help it centralise which will hep stop rolling..
