[frettchen]

I've wanted one of the jets ever since I went over there - as soon as I'm out of an apartment, I'm putting them on any and every toilet in my home.

I always kept some TP around, though, even when I was in places with the jets - but for the reason you mention the towel: it's handy to dry off with.

Well, and for sticking on shaving nicks or blowing your nose.

[latchkey]

No need to wait. It is just a T adapter. It screws into existing connections. There is usually a water shut off valve at the wall, just turn that off first. Just takes a basic wrench and some plumbers tape. It can all be undone just as easily.