which is better spare wheel?

[ckomai]

Right now I have my spare mounted on a 15" steel wheel that is obviously for a spare tire. You can pick up a stock wheel on ebay for 30-50 bucks. So my questions are:
How much weight would be saved from the steel to aluminum wheel?
If I had to run a long distance on the spare (offroad) would the stock wheel be much better than the steel wheel?

 

[Jason94sport]

As long as the steel rim as well as the spare tire are in good shape it should not matter.
I wouldn't bother unless you want a same rim spare for looks.. Even when I had 31's I used the stock steel rim with a 31" on it. Barley fit under the X, but it fit. Used it a few times, no issues.