I'm new to tuners and I am not sure how much power and/or stress they add to the motor. My car has the 2009-89-p...anybody know how aggressive this tune is?

 

That isn't as aggressive as a 91 or 93 race tune but it is more than the street tune. So you're right in the middle. The performance tune focuses more on the higher rpm range where the street tune focuses on the lower rpm range. The race tune is extremely aggressive as it focuses all throughout the rpms and has increased timing.

The power increase is going to be different on all cars depending on model and the mods done to the vehicle.