It really looks crazy messy under there doesn't it?
I'll give my opinion of your questions here:
1, From my own experience of MIM guitars, the pickups aren't always the greatest, and changing them for any branded aftermarket pickup should result in a better sound.(there are exceptions however, such as the MIM classic player strats)
Look carefully though at the height you have your pickups set, this can make a noticeable diiference if it's not right. Many people raise their pickups up too high,and lose sustain and dynamics in the process as the pull of the magnets chokes the strings' vibration.
I really would not be bothered paying any extra money for a signature set of Rory pickups, I'd save it and find a used set of 60s style vintage pickups by Seymour Duncan or the Fender Custom Shop 69 set..These 'over-wound' strat pickups lose alot of what makes a strat a strat (in my opinion)..you'll sacrifice some clarity and the ability to clean up the sound with the volume control with the hotter output. With the standard lower output pickups I think you get more range of sounds.
2.All traditional single coil pickups can be susceptible to noise, regardless of how old they are..it can be caused by noisy power and the resistors in stage lights.
Shielding can be done but I reckon that unless you're experiencing unacceptable noise right now I wouldn't bother. To get it done professionally can be costly, but if you're handy and have the tools and the time then maybe you could give it a go, there are many 'how to' tutorials available online.
3.Copper tape is regarded as the best method of shielding guitars...and due to the price of copper it's also the most expensive
4.it's hard to tell from the picture but considering that shielding paint is the same colour as that (black/grey) it probably is, I remember reading that Rory had some shielding work done on the strat somewhere on the west coast of the states during a tour.
I hope that helps you out,
All the best,
David.
