Suspension, guages and electronics would be all I would do if I knew I was doing a swap.
All power mods you try to make for an NA car will not transfer to a turbo car or will not be optimal once turbo. 3" exhaust on a NA car is not worth it at all, it will kill low end torque and only pick 1-3 hp up at the very end of the rev range. Borla and TWE headers can be used with RS turbo kits but not swaps, and these headers aren't optimal for turbo anyway. You might think about picking up a Cobb intake, use it for a year and then sell it, you will lose some cash on the deal, but not too much because the Cobbs will always be in demand and sell for good money.