Lower cost carpet options???

If you just want to cut noise, and not get fancy, deaden the main floors under the seat and under the feet, the little bit of heat from exhaust should pretty much be taken care of also.

If I was to lay carpet this way, I'd lay out the carpet 90 degrees to the hump either butted or overlap maybe 1" depending on how it came out. It may take a little more carpet, but it should lay much better, may be able to hide a seam or two, and it won't go sliding on you. Hey that rhymed! :)

Good luck, and let us know how it works out, and the cost of materials, please take some pics!