Hello,
It's all up to your preference. A lot of people have favorites. I would recommend getting a Porter Cable 7424xp. As for polishes and wax/sealants, find one that fits your budget. We carry a full line of products to detail your interior and exterior. All of our products are safe and extremely easy to use. We can always customize a kit for you to suit your needs. Here is an example of what our products can do to BMWs
2013 M3
Let me know if you have any questions! Thanks!
-Elliott