I'm pretty sure walang GPS yang Pioneer. I'm not too sure if you can have it as an external add-on though. The back-up camera is also an add-on module.

At the 20,000php range, your choice is either this or the Kenwood DDX 630WBT equivalent which has more or less the same features. Still, I'll vote for the Pioneer.

Alpine head units aren't affordable since they target more of the upper market. The nearest will be the Alpine W500 series and it'll cost significantly more (+40%). The reason for this is because those Alpine head units have great tuning features built-in. If you don't plan on utilizing them tho, they have zero value for you so best to get the Pioneer instead.