are these 8mm wires and are these good for my 99 DISCO II
 

No they are not 8mm, and no they are not good for your Rover.
www.apexperformance.net
Magnecor wires.

Ditto!!
8mm Magnacor wires are the best way to go.

I ordered mine from http://www.apexperformance.net/cartg...t.asp?scat=306

They have the best price I have found on the net.

what the downside of these wires I posted, bc i can get my hands on them for dirt cheap, the guy bought them but ended up selling his DISCO II so they're are still new in packaging and he's a local guy in my area. What is so bad about them, what will happen? I should still be able to get better MPG over the stock original gray ones, correct considering I just did the BOSCH +4 platinum upgrade last week.

You answered your own question, CHEAP, is exactly what they are.
We went round and round on this topic a while back. If you don't want to have problems, and you continue to ask for our help then do what we suggest, otherwise there is no reason for you to continue to post questions.

what kind of problems? Why would there be any problems since stock is 7mm and ive got 120k miles on it and (knock on wood) no problems with that department

The problem is that those wires will not hold up, they will most likly fail in a short amount of time.
7mm wires are stock size and you can use 7mm wires.
The Magnecor plug wires are a know to be a good and long lasting plug wire for our trucks.
At 120k it is VERY unlikly that those are the original plug wires on your truck.
You can buy those other wires for cheap and put them on and see what happens, its your call.

(2) questions about that:

1. How long will those 7mm plugs from Atlantic British that i posted last for? At least 30k miles?

2. Since I already did the BOSCH +4upgrade last week, if i were to replace the stock gray wires that are on the truck right now with the 7mm ones from Atlantic British, will my MPG improve?

The 8mm wires give better heat resistance.
Those wires from AB may last 60,000 miles, they may last 5,000 miles.
I have had my truck 2 years (28,000 miles) and have replaced my plug wires 5 times, I just ordered the 8mm Magnecor wires today.