The stock covers are pretty much no more than a piece of flimsy thin vinyl. As I was restoring some seats I looked around and found a seller on Ebay in the UK who made some very decent covers. These covers had piping at both ends and used a high quality marine grade vinyl as well.
On the seat I bought from Ebay, I stripped off the old cover, cleaned up the sponge and base, then reinforced the sponge at the nose of the seat where they all punch through and fitted one of the covers.
To staple these seats properly you need a forward facing handle type staple gun, the traditional rear facing types dont apply pressure over the staple as it should.
Here's the results of the work; the total cost on this project including the Ebay seat and cover, about $90.00. To buy and fit one of these covers to your existing seat would be about $30.00
Front edge piping, very evenly stitched with no waviness.
Rear piping, again very evenly stitched with no waviness.
Now that's a big improvement.
All nicely stapled in as it should be, all that's left to do is to fit the remaining seat rubbers and the battery cushion.