check both front and rear diff's just by turning the wheel and seeing how much resistance there is. If they both feel like they have the same resistance you should be ok.
some guys will tune their car with looser/tighter differentials but it can be difficult to master if youre not familiar with it, so just go for front and rear being the same for now
If anything run, the diff a little loose than a little too tight, as you can then try it for a lap, if it sounds like the motor is revving but not getting to speed properly bring it in, tighten and repeat until your happy
If you run the diff too tight from the start you can easily damage the thrust plates and balls
