I put in a new set of AC Delco plugs last year when I did wires. I just put headers in a couple weeks ago and when I pulled the plugs I found most of the pucks missing from them. With the gap then obviously being more than .050 the plugs looked pretty rich. Needless to say I won't be using Delco's in my car anymore.
Instead I put in a set of NGK TR55's. They are fairly inexpensive compared to the Delco (41-906). You should be able to get them at your local parts store for around $2ea. otherwise Summit usually has them in stock.
I put Taylor 8mm wires in last year. MSD 8.5mm superconductors are good wires also but they won't fit in your stock wire loom retainers without a little filing to the retainers.
I have no complaints with the Taylors so far, I got them from Summit for around $50. The MSD's are a little more.
One of the best Corvette techs in the nation told me to use the GM plugs... He talked about temp. range and some other things... I wanted to use bosch... He told me he would gladly charge to put them in, and gladly charge me to replace them in 20k miles... He said the GM platinum plugs were the best, and I would never have to replace them... This was on my '93 LT1