Why are you carrying a PSP? If you have a kit and never use the items, how do you know they’ll work when you need them? So much comes down to personal preference — I started with other kits, but liked DR’s PSP so I bought three. One I parted out to test, using some pieces as pocket carry and donating some pieces to supplement other kits. The other two were kept intact as parts of larger kits.

As regards individual items: I understand that DR’s PSP has a good whistle (Fox 40 Micro), but I prefer a Fox 40 Sharx, so I carry one of those instead.
The PSP has an excellent signal mirror. There are bigger/smaller available, but the PSP mirror is excellent and will do the job if you have sun.
When I have a need for making fire, I usually carry a couple lighters and stormproof type matches. The tinder in the PSP is very good if you use it correctly, then you need kindling & fuel. A good fire is all about the prep — tinder, kindling & fuel to maintain, or what’s the point.
Tools: Be it a Swiss Army Knife, a Leatherman MT or (fill in your preference), you need to be familiar with and comfortable using whatever tool you have. That tool should be outside the kit because it’s a user.

Look at your EDC in general and consider how the PSP fits in. Is it a supplement or is that your entire survival kit?