If your seat is a flat bottom and pretty straight forward, you can take the cover off, add 2-3 lifts of pink wall insulation under the old foam. Have a upholsterer (or if you're cheap like me - your wife) add a 6" strip of vinyl to the bottom of old seat cover, re-wrap the seat and staple it back up. You can get the pink foam in 2" widths, all you would need to do is cut it to fit under the seat and glue a couple of the lifts together with spray adhesive or construction glue (like a PL400), a full 8' sheet of the pink stuff costs about $30. You get to re-use the old cover to save costs (if its still in good enough shape).
Or take the cover off and use spray adhesive and glue new foam to the top of the seat, then use an electric knife to form the seat to your liking. This usually means you need to have (or make yourself) a new seat cover made since the look of the seat changes and usually you loose the wrap around portion at the back. This way you can change seat colours too though if you like or do a two tone thing.
Or you can just find a Rev seat and bolt it on.
The seat bolts onto the tunnel with "T" bolts and nuts towards the back. The usually are sucked into the wood base or plastic seat base, you might tear them out but you can buy replacement "T" nuts at the store and then just use a 1/4" bolt. If you go with method #1, you can replace the wood base on the seat with plastic or thinner and lighter wood as well.
Hope that helps.
