I tried the SLR. Light and comfy enough but one of the rails broke. I've gone back to using the Flite but the leather does seem to wear out quickly. My last one lasted less than a year.
If you are landing on your saddles while doing drops it's not the saddle I'd be worrying about. If you look at most of the DHers these days they are all using lightweight saddles.
What about the new SLR XC gelflow? The ad in this months MBR shows it has kevlar crash protection at the rear, a cut out for "plumbing" protection, and it (alledgedly) weighs in at 180 grammes. I have an SLK on my roadbike which I find superb. My MTBs have WTB rocket V stealths, which are very comfy but probably a bit heavy for a race bike.
I had a Rival with Titanium rails but was the roadies version and although very comfortable is in no way crash/scuff proof. Now put that on my road bike and am riding a WTB Speed V (OE fitment and not even close in comparison on comfort). If you go for the Specialised make sure you get your sit bones measured properly I thought being a big arse I would have needed the wider but came up as 143mm.