dying seats

im wanting to buy some new seats for my car but they dont match my interior. i was wondering if it could be possible to die the grey seats to red and would it last?

You could do that, but if you have seats, you should have them stripped, and simply re-upholstered with the fabric and color of your choice.

Not sure where you live, but most places (cities) have an upholstery shop.

There is also a thread called "custom interior" (probably not too far from this one)

https://www.the12volt.com/installbay/forum_posts.asp?tid=79897&PN=1

Check in there and ask "tony" (the person who made the thread) about it as well, he does interiors for a liiving, or at least hardcore hobby.

You would have trouble getting the right color red you want, using a dye.  Since your seats are already a dark color, you're finished color would come out dark.  For instance if you wanted a lighter red, and your seats are a darker grey, then you would be out of luck.  It would be easier to start with white.  Also you can run into trouble with uneven color throughout the material you're dying.  It would probably be best to just recover the seat.