Against my better judgement I will fess up. I work for GM, I am in Service Engineering, and I was one of the individuals that approved the wiring repair procedure for the recall on your Burbie.
1.) The recall should have nothing to do with your hard starting unless the dealer "fubar-ed" the wiring splice.
2.) Erratic gauge reading is the fuel level sensor. All vehicles have this issue to some extent - not just GM. The chemistry of today's fuels attack the metal content on the fuel level sensor and cause it to provide inaccurate readings. GM has made several improvements to their fuel level sensors in order to combat the stronger fuels.
3.) I do not believe an EGR is the cause of your concern. EGR will set a check engine light, code, or cause driveability concerns while driving.
4.) Do you have access to a TECH 2 scan tool? Does the vehicle run fine once started? Is the check engine light on? I believe you have a fuel delivery problem. 2000 burbies are fuel injected, no need to pump the pedal to start. I'm thinking injectors, fuel pressure regulator, etc. Heat around the starter is a bunch of crap. All starters are in a "heated" environment - they are designed for that.
Try to give me more specifics and I can dig into our databases and see what I can find. Diagnosing over the internet is tough though!
Feel free to IM me -thanks!
A good friend will come and bail you out of jail...but, a true friend will be sitting next to you saying, "Damn...that was fun!"