I'd suggest ordering the HU installation kit from Crutchfield. It comes with all of the cables you need, HU removal tools, the factory amp bypass, and detailed instructions. It costs about $20.
As for some drop-in speakers, I'd consider the
Crystal CSX570 coaxials at $62/pair. The dedicated outboard crossover is a really nice feature, and everyone who's used them has had very positive comments about them.