My 1999 Alero, has 15 inch tires on it. I can buy a set of 16 inch rims a tires from a 2002 Alero. Can I use these, if so will it hurt or change anything, such as the speedo ?

 

Your original tires size is P215-60-15, going to the optional 16" wheel should give a factory size P225-50-16 which will put you about .300 smaller in rolling diameter,it should not change your speedo to much, just slightly fast reading, also it should slightly handle better and give it a wider stance looking at it.

Just for reference front view of my Alero GLS (16" factory)

 

As noted, the diameter of the WHEEL is irrelevant. It's the rolling radius of the TIRE that matters. Keep that the same (or close as described above) and the car will never know the difference.

 

16 inchers, which ones painted GL2 or polished GLS?
To satisfy my curiosity.

Pat

 

polished. I bought the 4 of them with tires that have less then 5000 km on them for $250, which I thought to be a good deal.

 

Sounds like a great deal to me! Given that 50,000 mi tire would be around $140.00 installed.
Those rims should look like these.

Pat

 

Given my poor eye sight and the size of the picture you posted, I'd say that they definatly look the same. But I'm only basing that on the raised center cap.