If you're using one of the later versions of ISE 14.x series then the front end is already "Planahead". The options of making it the GUI look more Planahead like or ISE like is pretty much only cosmetic to present information according to the current usage of the tool, like for partitioning the design, choosing I/O etc.
Truth be told I wish they would have made Vivado support the 6 series parts. I really like the single executable model, the reduced memory footprint, the 3 dimensional placement/router, and the fact you can actual perform all the commands via a Tcl script that keeps the entire design in memory without having to wait for huge files to load for every single command. You can spit out checkpoints, which you can later load leaving you at the precise point you were when you wrote the checkpoint out. You don't even have to open the GUI if you don't want to, but if you do it's just a Tcl command away.