It depends on what you're looking to get out of adding forced induction to your car.
I wouldn't say it's a waste of money, but I will say that it's a significant investment on a car. If it's well taken care of - 135k miles is nothing.
So, I think you should really ask yourself,
"How long will I be keeping this car?"
"Have I looked into long term costs of maintenance for forced induction?"
"What kind of condition is the car in to start with?"
@Loud3 My whole goal was to make a better performance car, but once I looked into maintenance I realized that probably would be better to just leave it stock and save up for a MazdaSpeed3. Thank you for your input