If you have a few guys playing with you at the same time in FSY then it's fun.. otherwise, my suggestion is "Don't put a 1:10 EP in the track"...... Those crazy nuts with 1:8 and 1:5 will eat you alive!!!
I usually bring my DF03 in FSY as backup.... but most of the time I ended up with my 1:5/1:8 anyway.....
As for the 501, I have my doubt in terms of the belt drive design.... in FSY, the chassis likely are twisted all the time and I wonder how long the belt will last...
If you really want to stay with EP, get a E-zilla or E-Savage or E-Maxx would be your only choice......