I have some questions to the community. Getting 2001 with 67K miles on it and would like to make it move a bit faster(not what it needs it). SC is too rich for my blood - just truing to give a car a bit more zip.

Performance mods - from what I have found so far there are following mods availiable - Headers, AirBox from W211, X-Pipe, and pulley. How much power gain and drivability change I could expect from this modes?
Are they safe for the car? Any disadvantages?
Also - does anybody tunes ECU on this cars? Any way to improve tranny shifting on the budjet
What tire recomendations do you guys have?
Better handling without killing ride quality?

We are expecting baby in next 2 weeks so I need to put together cookbook type of recipy of what I will do with a car, come up with a plan and allocate budjet(hide $$$ from my wife ))))))))) - I'm not going to have much time after baby born

Idealy looking to chat with sombody who curently owns a modified one - feel free to chat with me in ICQ - 127-141-200, Skype - lcatga or call me on my cell - 516-650-6204 between 1PM-2AM EST
Leon