The Boss 351 model kit is a Revell-Germany kit which historically has built a better fitting more detailed model overall than Revell-Monogram. I feel that the Revell-Germany models are worth the extra investment, when they are available. The 1971 Mustang is made in 1/25 scale by AMT, Revell-Monogram and Revell Germany, and maybe other companies that I am not aware of. IMO, it is a good, better, best scenario, based on overall model kit production reputation. In my experience, AMT is the kit I bought if no one else made the year and model that I wanted to build, then Revell-Monogram. If Revell-Germany offered a kit for the car I wanted to build, that is the one I always went with, a little pricier but I usually found it was worth it.
Also, the listing for the Boss is for the model set, the set includes paint and glue. I usually like to buy just the model kit and use my own paint and airbrush and supplies. If you don't build a lot of models then the kit may be more convenient for you.
