I'm very pleased with the new boat seats I ordered last summer through Amazon. Tempress NaviStyle highback seats.
They were about 100 bucks each but well worth it. Well made, plenty of good firm padding, and they're even made in America with a little American flag tag sewn into the backrest.
I put those same seats in my sled this Spring too. My old seats were 13 years old and still ok but looked tired.
check Amazon.
