I have the standard seat package (no leather, no lumbar, no heat). I'm fine with the seats as is, except that valley where the bottom meets the back doesn't go well with my posture. For now I rolled up a medium sized hand towel and shoved it in there to fill in that space (so now the shape just continues without the valley) -- but its only a short term solution. Does anyone have suggestions where I can find a small thin cushion (or something else) that can fit in the seat valley? I'm not looking for lumbar cushions or anything that would stick out beyond the normal seat contours. Thanks!