Congratulations on your new purchase!
For the tach problem, you can do a search on this subject and find a bunch of info, including a possible temporary fix, and another one on possibly being able to repair it yourself. As far as the trip odo goes, after removing my cluster and taking a gender at all of the parts invilved, it turned out that a little wheel had undone it self. I pushed it firmly back into place and so far it has worked for about 50k miles with no problems. I have yet to figure out why there is an antenna switch, when on my car, whenever I turn on the radio, the antenna goes up automatically...even if I try to lower the antenna by pressing the switch, it just goes back up again. (weird) There are some repair kits for the power antenna, depending on the type of problem that you may have (a closer inspection of connections is warranted).
Have fun! (and remember to use OEM parts)
"...rationality of thought imposes a limit on a person's concept of his relation to the cosmos." -Nash
04/71 280SE 195k
09 Jetta TDI