the only picture i took after fitting, was of the actual gauge in my car. (link in my sig if you're interested)
it was simple to plumb in though.
i simply took a knife to the pipe in question and cut straight through. i then joined the pipe back together with a t-piece thingy (not sure if the proper name) and put the pipe from my gauge into the join as well.
to make sure everything is held together nicely, i got a couple of jubilee clips and put them over where the t-piece goes into the original pipes (if that makes sense?)
the bit that was most difficult was feeding the pipe to the gauge through that little grommet hole. god knows how many wires are going through there now lol
good luck.