I agree with above on getting the catback instead of just mufflers, it does make a difference.
The J mod is great for auto's, its cheap, easy, and it works. I haven't had much luck with shift kits on these cars.
You probably can't use your friend's tuner, unless he returns his car to stock and keeps it that way, the tuner can only be used to tune or alter one vehicle, until it is used to return the first vehicle to stock.
I would add subframe connectors to your list, a very important and oft overlooked mod.
If you can I would also think about lowering the car, it makes a huge difference for the better in the way it looks and feels.
When you're starting out modding the car its best to go with things that you'll enjoy the most. Things like gears, shifter, tuning, and springs are big impact items, you feel the difference all the time you drive, gets you more out of your money.
The artist formerly known as SteedaMatt.