gort

I'm looking for some advice on doing a complete swap out of the stereo in my 2000 TT Mark I. I have a non-Bose system, the front couple of speakers are blown and it's a cassette - need I say more? I'm looking for a middle of the road single din that fits the dash so I can still close the flip lid. A lot of sites aren't exactly clear and some say the dash needs a major rework ... I'm not so sure about major! Dash kit, yup, but I have to have the flip lid closing. Part of the reason I bought the car!
I'm also a little perplexed about the "K Line" issue ... lots of opinions on that and most installers I've talked to just give me the blank stare.
I want to do this right and not blow up some guys diagnostic tool if I go into a mechanic for something.
So any and all advice is welcome and appreciated - be kind please, this is my first post in this site!
Thanks, frank