Need someone to explain to me exactly what slip on's are, because I'm almost 100% sure they dont "slip on"

 

slip on is midpipe back--- the "slip-on" part just emphasizing the simplicity of it.

Full exhaust is everything including headers.

For the average rider the only thing a full exhaust will do is give a bit more of deep and throaty note vs the same exhaust but just the slip on form.

I went for the full exhaust.