Just my thoughts....but if you are going to try to go the turbo route in a couple of months.....then I would suggest you wait. That way you can ask the installers on their experiences with different systems or they might have a system already to go with that turbo system.
Try not to put the cart ahead of the horse. Even if you get an exhaust system with going the turbo route in the future...it still might not be the one that with match well with that particular system.
If you absolutely have to do something...then I guess I would suggest a HFC with stock exhaust since you are going to have to use a cat either way depending on your state emission laws.
Currently if you use an exhaust that is too free flowing...then normally yes you will "loose" power. Torque on the bottom end will usually drop and the gains in HP will also usually only be in the top end of the RPM range. An area that you will not be most of the time and therefore you will perceive a "loss" in power. Possibly to the point where you will have to shift more often to compensate for the difference.
All in all....its going to be your choice and you are going to do what you want to do. But if you are going to install a turbo kit, then I would suggest you wait to touch bases with the installer on what would be a good match. Depending on your HP goals...most of the exhaust systems on the market coupled with test pipes might be more than adequate enough.
Just my opinions though. Best of luck in the turbo department. Make sure that you choose a good management system and an even better installer/tuner.
