It can be added and it's barely noticeable until you're sitting in it.No lumbar support.
I don't know if I would go that far but I do agree if they are in good condition they are comfortable. I've purchased two GT's with different seats in them and had to replace both with OE seats so that we could get comfortable in them.Lies! The GT seats are super comfy. I’ve though about making an office chair out of one. Now my Tacoma’s seats destroy my back on road trips lol.