SEC as in W126 or W140. Personally, I don't own those two cars, but luckily, I have driven them all. In my opinion, W140 SEC is way more comfort, luxury, and more power. However, they bring top dollar if well looked after. As for W126, somehow(I maybe wrong) I feel that 560SEC is alot more power, and runs more smooth then 500SEC. It's like as if 500SEC is running on in-line 6 compare to 560SEC. Lee, what do you say??