I'm not sure traxxas steel pinions will hold up to a steel spur. You may want to get robinson racing's hardened pinions. .8mod or 32 pitch.
For what it's worth, I use RRP's on my stampede with 3S which has a plastic spur and both hold up fine. I also run an RRP pinion on my savage flux hp (1M/5mm) against HPI's steel spur and it holds up fine as well.
I prefer a plastic spur if I can get away with it. Less rotational mass, quieter and a cheaper breakage point in the drive train.
For what it's worth, I use RRP's on my stampede with 3S which has a plastic spur and both hold up fine. I also run an RRP pinion on my savage flux hp (1M/5mm) against HPI's steel spur and it holds up fine as well.
I prefer a plastic spur if I can get away with it. Less rotational mass, quieter and a cheaper breakage point in the drive train.