I have heard of, but not yet seen, the "big" seats for SPFs. Do they look the same as the traditional SPF low-back seat? The only Superformance seat I have been in was just too narrow for me, and I'm only a 40" waist
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The side "bolsters" that curve around from the lower half of the the seat back and connect to the seat bottom constrain my caboose. Probably great for racin', but not so much for cruisin'.