Nothing has gone wrong, knock on wood...
I also owned a 1999 Pontiac Gran Prix and to be honest it was a better vehicle than the newer version. The stereo system was much better so I was disappointed with this. The 199 model topped out at 140 and the 2002 tops out at 105.
I cannot believe that GM changed this model in 2005?
You shouldn't be driving at 140 or 105 anyway.
I can't believe Pontiac changed both the Grand Prix and Grand Am. The pre-2004 Grand Prixs were the best-looking 4-door car ever built. The new ones are nowhere near as sporty or well-designed. The Grand Am (pre-2003 with the body cladding) was such a pleasant change from all the look-a-like, boring compacts, and now Pontiac has dropped it for the ugly and unappealing G-6 that looks just like all the other little ugly compacts. I won't be buying another Pontiac until they hire some new designers.