rgaus,
Many thanks for your diligent research! My guestimate was based on where I thought my butt might end up, accounting for "give" in the cushion. This figure may of course vary depending on the butt

.
On the subject of wieght, can you shed some light on the wieght difference between old and new model smarts. I thought I'd seen a 500lbs increase quoted, but the manufacturer's specs indicate somewhere in the range 50 to 100 lbs. I realize this is not an exact science, since we're not comparing apples with apples based on equipment, engine, etc. Also, with the 450 the cabrio and coupe had (allegedly) the same curb wieght, but the 451 cabrio is quoted as 66 lbs heavier than the coupe.
Any insight would be appreciated....