I have a DEI 562T in mine and I love it. Installed it a couple of years ago. I got the bypass box so I don't have a key tied up in the system.
I actually hated the Key/fob combo crap on my 2007, so I picked up a grey-headed Sentry key and use the remote starter remote with it. So, I have 2 spares
Also, with the DEI unit you can wire it up so that you can use your OEM fob if you wished....you'd have to hit the lock button two or three times (user preference) and it could trigger a start.
It's certainly doable if you're interested in doing it yourself, but it's not simple by any means.