2017 Ram 2500- Airbag Question

I have a 2017 ram 2500 with coil springs and im going to put airbags on it. Les schwab said they have air bags that go right in the middle of the coil spring and I have also seen pictures of air bags installed between the tire and coil spring. Is there an advantage to either one? Les schwab quoted me $498 installed for inside of spring but havent price check outside of springs.