No infact the exact oppisite is true, the less restriction on a turbo the better thats why diesel's have such huge air filters .... to eliminate intake restriction. Having an oversized exhaust will help turbo spool and help eliminate turbo lag and increase power, torque, and mpg's.....
You want the biggest air cleaner thats feesable with the biggest filter area possible. and exhaust with bigger piping and less bends or pinch points will also reduce the EGT(exhaust gas tempratures), meaning less wear on your engine, also running a good synthetic oil will help with friction and mpg's improvement also.
Wide open is the game...... in or out of a turbo just rember that k..... smaller is slower and hotter.... keep rockin