Actually, besides the firmware and drivers, there aren't any updates that are specific to the SP3. An update labeled "Option" on up to "Critical" is addressing something in the operating system.
I know a lot of people complain about systems slowing after updates, but I have found a way to get things back on track. It just takes time. But the process is simple.
On a fresh system, run the "Disk Cleanup" program and under the "Clean up System Files" select everything and let it run. Then "Defragment and Optimize Drives" (with a SSD you just run the 'trim' process).
Then go after the first round of updates, and let the system reboot. Make sure you log in and let it sit for a few and let the update process finish (there are some things in the update process that still have to happen in the background after you log in).
You then repeat the "Disk Cleanup" and "Defragment and Optimize Drives" process again.
Then back to the updates. You keep repeating the process till there are no more updates to apply. You end up with a system that is fully patched and defraged and runs quickly. This is when you might want to use some disk imaging software and make an image of your disk and archive it for recovery sake.
After all of that, go install any full screen apps and desktop programs. Again doing a defrag after each install if you really want to have a lightning fast system. The main problem with the defrag is if you have a spinning disk as it can take awhile each time.