you will also need...
-coolant
-$100 for head gaskets
-11qts of oil and 2 filters(1 to use to wash down lifter valley) (4.5qts to change with right away) (another 4.5qts to change in 500-1k miles)
-pcm tune (unless you have a tuner) I run a top-swap tune from Intense, it cost $200
While your at it, you might as well get new ls7 lifters as well. Paceperformance has them for an awesome price.
The only wiring upgrade you need is a Map sensor adapter.
As far as cylinder heads, get the 98 and up style ones. The 97's crack around the valves (some say it doesn't matter but, if im paying all that money i don't want to put on cracked cylinder heads)
It would be wise for you to get your cylinder heads machined, fluxed, and checked for cracks. That cost me $190 but its well worth your investment.