I'm going to keep my outside stock cover on my 2014 Ultra Limited. What is the difference between stock backing plate and the backing plate you get from Harley for stage1. Why can't I just get the filter and install it using stock backing plate. Yes this is my first Harley so I'm needing education and info.

 

The stage I backing plate eliminates the plastic back part and allows air to come from the whole backside of the cover instead of just through the small inlet

 

As HT said.

But save your money...you'll get nothing of consequence except a lighter wallet for your purchase and effort.