Yep blue caps arent original. That orange sprague cap and those large green caps also look suspect. Someone didn't know those circuits don't require caps that are rated for nearly that high voltage...lol
If you search for tubescreamer and ts9 mods you'll easily find all this info on the net. I did this about 5 or 6 years ago and swapped a pile of parts on my ts9 to see what each did and whether I liked it or not - a fun little project and resulted in a way better sounding pedal. not to take anything away from those who already provide these services such as keeley and analogman, but I figured this isn't rocket science. lots of info on the DIY pedal sites and there are numerous gut shots and pictorials of this. If I remember from mine it looks like most of the audio circuit caps were upgraded to higher grade versions - doesn't make much difference that they are larger higher voltage rated from what I was told by an amp builder/tech I bought my parts from.