NEW AUGUST 2021 SIRRUS X 5.0 EXPERIENCE
Last June I put a deposit down for a medium blue Sirrus X 5.0 for my wifes birthday in July. My LBS had one in the pipeline with no idea when it would arrive, but it had been on order for a while. Around 3 weeks ago my wife said that with these shortages and the long waits, I should put in for a bike for myself now for my birthday in January, so I did. 2 weeks ago I get a call from my LBS. They got 5 redwood ones in with no warning (not the blue one that had been on order), and two of them could be ours if we wanted them. My wife set aside her dislike for orange and we picked them up a week ago. All 5 went to people who had been waiting. .Here are some notes that might be helpful to others based both on my initial experience and some questions that I have seen on this thread.

1.Prior complaints about cheap no-name cranksets on such a nice frame . The ones comming in now have the real Praxis Alba bottom brackets and cranks. Not top of the line, but certainly not the previous no-name crap. The pedals are still meh, but I would have replaced them anyway. To me the bike is very ridable stock, even the saddle. I rode mine stock for a week just to see, but then I did end up moving a few things from my old bike, including my Selle Royal Respiro saddle, shockstop suspension seatpost, and Diety Supracrush grips. My wife is riding hers stock and is happy so far, although when I finish dialing mine in I will start convincing her to be unhappy
2.Size - I have seen debates on Sirrus X models running larger than spec. The examples I saw were 4.0s. I was worried about me having a large given that I am 5-10, 32 inseam. I seem to be fine on the large 5.0. Sitting on my wifes medium, I could have ridden it but would have probably have needed a riser stem as getting the seat high enough would have put me too high above the bars even with the headset at the highest allowed level. At 5-6 1/2, my wife is fine with the medium. I am wondering if there is a difference between the carbon 5.0 and aluminum 4.0 frames.
3.Internal cable rattle. I haven't noticed any on either bike, and I ride some pretty rough gravel roads. I did notice a little spring noise after first installing one of the future shock helper springs, but it disappeared quickly. The next time I am at my LBS I will ask if they noticed any design change in how the cables are run in the downtube when they were built.
4.My LBS told me that I was not to touch anything having to do with the Future Shock or it would void the warranty. Bring it in for everything. I asked if that included things like changing out the helper springs (very trivial) or adding headset spacers, which does requires you to loosen and remove the future shock and possibly monkey with the preload bolts (although it wasn't necessary for me). THey said yes, those were off limits. This seem ridiculous, especially chaging out the springs as you simply unbolt the stem and remove a cover; you don't even loosen the headset. So... I emailed Specialized support. THey said changing the springs was fine as well as raising the stem height as long as I knew what I was doing with a torque wrench. Note that I would NOT go against my LBS recomendations without a get-out-of-jail email from Specialized, so YMMV. My guess is that their issues come with people opening the main body of the future shock (which is not serviceable) and people messing up the clamp torque and preload bolts as they are tiny parts (and the clamp sits on a carbon fork tube). I would highly recommend becomming very familiar with all of the parts of the future shock and headset before messing with anything as it is nothing like a normal headset. It is very different, but once you understand it everything makes sense.
5.Parts bag. THe manual they give you is generic for all their bikes, and the X 5.0 comes with a bunch of extra parts, the uses of which become obvious after a while, but why not describe them? The Future shock helper springs are in a bag inside a bag. The outer bag also includes a tiny wrench that is used for the future shock preload bolts when you lock them, a shim that is used to adapt standard stems to the future shock (there is a shim installed for the Future stem as well, but its a different size), a pair of valve stems to be used for tubeless setup, and three 5mm headset spacers. The spacers are not standard, and the three together provide the maximum 15mm that are allowed. In ONE of my two bikes, I noticed an oval piece of hellicopter tape. On the other bike, it had been installed on the headset tube where the cables have potential to rub. I installed the other one, but it seems too small to me, so I'll probably use a large piece when I tape other parts of the bike.
6.Seatpost clamp. The seatpost clamp sits inside the carbon seat tube. Mine has a tendency to want to fall into the seat tube if the seatpost is removed. Just be aware.
7.Is the furture shock a gimick? People seem to hate it or love it. My wife claims that she doesn't see a huge difference, but she went months between riding her old and new bike due to a hip surgery. For me...it certainly doesn't make my gravel bumpy roads feel smooth, but there is a pronounced difference in how beat up I feel at the end of the ride. A big difference. How much of that is due to the future shock versus the carbon frame is hard to say. I prefer using the helper springs (trying to decide between weak and medium) not because I was bottoming out, but because I found it to minimize the effect on handling without any noticable comfort penalty. THe default configuration is no helper springs.

I hope this helps someone. I tried to post a picture of the bikes but I don't have enough posts yet.