Mattress Forum

For years I've slept on air mattress pads while backpacking, rafting, etc; I sleep well and my back seems to like it.  So I've been interested in SleepNumber beds and wondered if they'd be a good choice for me.   Recently I picked up a used one for a ridiculously-low price, and indeed my wife and I like it very much.  It's labeled as a "5000 model", bought around 2005 according to seller; the comfort layer is 2-inches of what looks to be ordinary foam.  Only problem is, it's a king-size, which we definitely don't want.   We want to get a queen-size mattress-only and use it on our existing platform bed.  I'm a bit confused about their models.

Looks like the "c2" might be the closest thing.  But when I called to ask why I couldn't have it shipped and assemble myself, as I've heard suggested to pay $90 shipping instead of $200 delivery&setup, I was told the mattress comes as a fully-assembled unit, in other words it's the same size as an ordinary queen-size mattress so can't be shipped by normal means.  So maybe it's not so similar to the 5000.   

If you poke a little deeper in their website you find "Value Beds"; those aparently do come shipped in boxes to assemble yourself.    The "s1" is actually the same price as the current $100-off promotion of the c2 (except the shipping is free).   But after reading Consumer Reports' very negative comments on the "IT Bed by Sleep Number", it kind appears to be the same thing: you order it online, it comes in a box, and you assemble it yourself.  Of course, the IT Bed is discontinued, so I wonder if the "s1" is some model-renaming subterfuge.

I guess I should just eat the extra $200 for the "c2" to make sure I like it, but I'm curious on others' knowledge/experience about all this.   Thanks.

P.S. My platform bed i very sturdy, built myself with 2x4 slats and about 1" spacing; will that be suitable for the Sleep Number mattress, or do I need to put a piece of plywood underneath ?