exhaust? gas mileage improvement? 4wd?

[blockburna]

I was considereing getting a cat back exhaust system for a 02 Suburban 5.3 (I will be buying soon) and I wanted some opinions on different systems. I do not want anything thats to loud on the inside because I will be traveling with it.
How much would a cat back or intake help with gas mileage? What else helps with gas mileage?
Also do you know of any suburban / tahoe / silverado / avalanche web sites?
Do you think a 4wd is really worth it if the truck will only be driven on road? I was thinking I would be better for snowy or rainy weather. How many of you actually use 4wd on road?

[J-Ri]

This is the Avalanche forum, not the Suburban forum. That said, 4x4 is not for wet pavement driving at all. I have only been on icy roads twice that were bad enough to leave it in 4x4. NEVER use 4x4 if you can see the pavement. The ONLY time I use 4x4 is if 4x2 won't move me any more, or if there's almost no traction (a sheet of ice, really soupy mud, etc.). And I'll tell you one thing that doesn't help with gas milage: 4x4 (a transfer case, extra driveshaft, and extra drive axle add a lot of weight).