1-2 shift chirp, Tire update, Polishing, & Diff. fluid

[apstguy]

I have found out that with these skinny tires from the Tahoe, if I am turning and give it a little gas, the 1st-2nd shift will chirp. With a 305? What gives? It's really cool, but a 305? No muffler did give it horsepower! Hehe...

Anyways, I did get my one tire that poped - ended up being $87. I still have the junk tires on (making me squeak everywhere and peel out when there is paint from a crosswalk)

I am polishing my rims, but only have 2 done. They took me 2 hours each doing a half ass job! Is there an easier way to do this? I'm using Nevr-Dull w/ the cotton or whatever it is that comes in a can. Works well, but takes forever and alot of it! I can't get the holes clean. Any suggestions?

I'm changing the differential fluid out this weekend. I don't think it ever has been changed, so It may have solidified a little (I've seen it before!) I'm a little afraid. I'm going to use 80W-90. The right stuff? I think the bottle I got was partially synthetic. Any positives & negatives associated with it?