04 front seat conversion SR5

Have been trying to find a solution for uncomfortable seat on long rides. Had seats bottoms replaced by upholstery shop with OEM parts. They are still uncomfortable on long rides. looked
at replacing with 04 Sequoia seats (power). But most looked at used had 150,000 + on them and would have to be rebuilt(spring/Pad) with questionable results and some of these parts being discontinued. Thought had found solution with Discount Truck (AZ) they have fabulous seats . all American made( high resilence foam/double tube frames,7 spring base powered lumbar). Unfortunately, they only make the adapter bases for Dodge-Ford -Chevy (very good ones that meet Federal std.) Has anyone ever tried to make or know someone who fabricates
these? it would be difficult to make as they would have to be adjustable(slider) and withstand a heavy collision. Have even toyed with buying new Tundra but have read they have same issues.
Any thoughts on this would be appreciated. Was kind of shocked that as many Tundra customers as there are out there and they dont make and told company such. They would cost about $2,900 with Hi-Resilence foam, leather, power lumbar and 7 spring but they seem like the solution .The adapters they had available for other brands were very reasonable(< $75)
There seems to have been quite a few discussions on the forum about comfortable seats.
As much as they get for New Tundras you would think they really be great. THX