I had a pair of the 265 kicks. I love the silk tweeters, and still use them. they were not very harsh at all. the midbass was pretty good, but that is dependent partly on install. i ran 100w a side to mine and it sounded great.
i use welding wire for my power/ground all the time...the 0/1 i use is plenty flexible. i guess if it sucks compared to the other stuff than it must be absolutely amazing.
true, if your already going to be running 0/1 in your car, just run it all the way. its better to have too thick of a wire than to have too thin. insurance if you will.
how long will the wire be? if its short, you should be fine.
edit: this is the sticky at the top of the page regarding wire sizes http://www.caraudio.com/forum/showthread.php?t=166038
ya corrosion is not good for your battery. just check it every so often and make sure its clean. you can also put some grease on it i believe...but that can be kind of messy looking.