Try cars.com, nada.com and kellybluebook.com. I may have miss-spelled the last one (kelly may have only one "L").
I think all of them will give you MSRP, invoice price, and info about horsepower, weight, etc. Some have reviews also.
Also, Kiplingers (hard copy mag) used to put out an annual review of cars each October. It may be on their site, but I've never looked there.
Good luck
CB