I run Spektrum servos as well and the servo lead is too short for Tekno vehicles. Use a short 3" servo lead extension and you are all set.
The battery straps are long, but when you get a hard case 4s battery, they work and hold well.
Also, ditch the plastic servo horn. Get a Tekno alu horn, they work great and are strong. The big truggy tires will strip that horn quickly in a crash.