I just purchased three more PSP's, one for each car and one for training, sorry... teaching the DW. I have tried adding several different items and now this is what I carry in addition to everything already in the kit...

mini Bic lighter
(6) Micropur tabs
(2) Gerber bags

I would not consider adding any additional knives/tools as I already EDC a folding knife and a mini multi tool on a key chain (as well as other things that I will post later as soon as I can get the digital camera to work). I would love to know if anyone else has been able to add extra stuff to this great kit.