Slipper and tranny questions

I have been searching around with not alot of success in finding answers to my question.

I stripped out my 2nd gear idler and would like to know if a good slipper will stop stpipping the stock gears?
I cant find any metal idler gear so I was hoping a nice slipper will work.

If I go with the stobe slipper I am somewhat confused about the gearing. Right now I am running a 66th with a 16t and it works fine. IF I go the slipper route what would be the same gear ratio. Also what type of gear do I need for the motor 8XL. I read mod1 mod2 ... not sure??

How much better is the stobe vs the RRP one?