Need some help with the new spur gear for my Savage X 4.6, was looking at two different:

http://www.rcplanet.com/HPI_Heavy_Duty_Spur_Gear_47_Tooth_p/hpi77127.htm

Or:

http://www.rcplanet.com/HPI_Steel_Spur_Gear_Set_p/hpi86807.htm

The second gear costs twice as much as the first gear and i was wondering, since i'm still a newbie at nitro, if there is any differences in the quality of the gears. Could also need some help with the amount of teeth on the gears.
I will also upgrade to a HPI Racing Clutch Bell, maybe 17 tooth, what do you guys think about going with stock tooth number on both spur gear and clutch bell gear?