1/8 Buggy Tire/Wheel weight?

David,
I am more interested in reducing weight to put less strain on the motor. The buggy is at 9.3 lbs, there is fat to be cut, I want to find out where. I know there are several things I could do to cut weight more drastically, but I also want to fully evaluate all possibilities before going further. Also, looking at the data below, my tires are actually 1.09-1.1lbs, while his were .86lbs, that might be enough of a difference for me to care, especially sense that is rotating mass, that has much more effect then say the same weight difference on something "stationary" like the batteries.
Definition of stationary in that example-object that does not move relative the buggy.
And to update my tires:
Weight-1.1lb(499.7g)
Number of tires- 4
Tire brand-unknown
model-"racing spikes" (see here)please note: this link goes to an ebay page, it is not my ebay page, but it is the product I purchased, I am not endorsing this product or trying to sell it to you.
Rim brand-unknown
Type (type=dish/spoke, ect)-Dish
Rubber-medium compound
Condition-New

Weight-1.09lb(494.5g)
Number of tires- 4
Tire brand-unknown
model-"Mohawk" (see here)please note: this link goes to an ebay page, it is not my ebay page, but it is the product I purchased, I am not endorsing this product or trying to sell it to you.
Rim brand-unknown
Type (type=dish/spoke, ect)-Spoke
Rubber-medium compound
Condition-99.9% new (no wear)

If my post is confusing I apologize, I just sat in a 6-8 room for 8 hours watching iron pellets come out of a tube (more complicated then that obviously). Now I have to work another 6ish hours before I go home and start the process again tonight. AKA I am not necessarily in the correct frame of mind.