That's where you're wrong.

how many brains do you have?

You're welcome

Tomorrow is the 15th anniversary sale on AliExpress. If you're planning to buy something, here are some new codes:

Yay nice discounts.  Got a Xcadey PM+chainring for $250 delivered, woohoo

So I'm very inexperienced in this area of bike mechanics... but according to my LBS, I could use a replacement for my existing Shimano HG800 11-speed

https://www.trekbikes.com/us/en_US/equipment/cycling-components/bike-cassettes-freewheels/shimano-hg800-11-speed-bicycle-cassette/p/560043/

Can I replace it with this Ali Express cassette?

https://www.aliexpress.us/item/3256807353803495.html?spm=a2g0o.productlist.main.1.50f0RmCyRmCyXd&algo_pvid=7577c372-de27-4f00-bceb-c46757be7d0a&algo_exp_id=7577c372-de27-4f00-bceb-c46757be7d0a-0&pdp_npi=4%40dis%21USD%2169.77%2130.99%21%21%21505.58%21224.56%21%402101e7f617377570004642162e2e0e%2112000041213348616%21sea%21US%210%21ABX&curPageLogUid=OhfVACAv6V4Y&utparam-url=scene%3Asearch%7Cquery_from%3A

I also only use 2-3 gears in my very flat town, would it be worth considering a cassette with a narrower range?

What's your front chainring?  personally for me 11-30 with 50-36 at front, 36-30 is good for 15% gradients for me at decent cadence. 

I have been frequenting forums and buying Chinese products for over 10 years but the XDS brand is the first time I have heard of it.

Yep same almost. Built my first Chinese roadie FM066-SL like eons ago, and never heard of XDS till the recent China Cycling vid that peaked my interest, hence the ask.  Some people need to get over themselves.

Looking for some replacement pedals for my tired Look Keos.

Does anyone have any experience with these or have some recommendations?

https://www.aliexpress.us/item/3256805275057695.html?spm=a2g0o.productlist.main.1.6a88MZGWMZGW0r&algo_pvid=be3cf61d-c86e-4561-9419-8e4649174cc4&algo_exp_id=be3cf61d-c86e-4561-9419-8e4649174cc4-0&pdp_npi=4%40dis%21USD%2128.04%2128.04%21%21%21199.32%21199.32%21%402101c80017302175432861035e4b0d%2112000033176120712%21sea%21US%21190578016%21X&curPageLogUid=3hFwbCYbnSmS&utparam-url=scene%3Asearch%7Cquery_from%3A

I've been riding this frame (branded as Allebike) for over 2 years now, racing, training, audax. From the frame quality perspective it is good - brake mounts, bottom bracket, headtube are all faced and round as it supposed to be. The ride is rather stiff on both front and rear end of the bike, which is expected from such tube shapes. For shorter races it is absolutely okay, but my butt was beaten to death on race-paced audax on really shitty roads. Steering is confident but more on a slow side.
The issue I had with it is the crack which emerged on the top side of the top tube. Seatpost clamp started to push on the tube which caused the damage. My local carbon expert is fixing it now. He has seen such issue twice (on Colnagos) and he mentioned it due to insufficient amount of carbon layers in the area.
On the other (smaller) notes:
- Seatpost allows for tremendous fore/aft adjustment but ugly as hell. I believe such thing belongs to TT bikes only. The saddleclamp is very stiff to lateral movement of the rails and if you want to make small adjustment on the go you have to disassemble the whole clamping system. It is easier to move the whole clamp for for/aft adjustment, but then to reach the bolts (which are located underneath the saddle body) you need very short (if a saddle has no cutoff) or very long hex key (if saddle has cutoff).
- The seatpost clamp bolt is located VERY deep in the top tube. It is not possible to reach it with a regular multitool. Same applies to the torque wrench.
- The frame has thin (to modern standards) down tube and is not optimised for regular bottle. You may consider aero bottles if it bothers you.
- Derailleur hanger is not a perfect fit for the frame, it has some play with only two mounting bolts, but once you clamp the axle it is fine, no issues with the shifting perfomance.
Flexing tubes, especially on not stressed areas, is fine. I have owned several top end branded bikes and they all have very thin carbon in some places, you can flex it with your tumb quite easily.

Thanks looks like some quality issues with the seatpost and I dont like the look of the seatpost either. 

Seems like it would be easier to have the manufacturer send a video with their own boroscope. Then you dont have to buy a camera or go through the hassle of swapping frames. And it will force them to step up their QC

Maybe ignorant on my part but knock on wood I havent heard of any issues with structural integrity on Chinese frames recently. I think these companies get that injuring/maiming/killing their customer base is prob not good for business. And they are not new to the game either. Maybe Im too optimistic

That's unrealistic given the amount of frames made, the time and labor effort required.  Best chances are to get your own, inspect and get a replacement if problems arise.

whats the promotion?