You can do it now if you want, but if your going to get a turbo and injectors right round the corner may as well save the $300-$500 on tuning until you got it all ready...
But hey if we are talking 6 months til you do that then you may as well go get it done now, you will be supprised how much more you can get out of a stock setup with just a pfc over the standard ECU...
As for installing the pfc it self, do it youself it takes 5-10 minutes to actually plug it in and then 10 minutes of the car at idle then 10 minutes with the car at idle and the A/C on, and your ready to drive it to the tuner. Just dont drive it to Sydney and back on base maps thats all, the maps are safe to drive on just dont load it up or drive for weeks on it like this...