Just ordered tekin 2050 buggy system

[rcobscession]

I just ordered the 2050 buggy combo for my hyp 9e. I will be running 6500 35c hyperion 4s or 5000 5s. With the stock 40t spur what would be a good pinion to start with. Also, i ordered from mike since he seems to have the cheapest price around. Props to RCMONSTER. Are the ones that mike is selling now have the newest upgrades ie new case ect? This is my first experience with anything tekin and i am used to either castle or mgm so we'll see how it goes.