Hi bro DaRkN3Zs, here is my idea and recommend:
First, which type gear box you are using? AT or MT?
If only modifying the exhaust pipe and the muffler is hard to bring the true power of N/A engine, even you are using two bullet, but all cyclinder still using the same extractor, so the power are not increase much, but a little bit lah ^_^.
About the "super air charger", I think you can put it away, this thing allow more air by pass the throtle valve and direct go inside the engine, but this will make the engine ECU (engine control unit) confuse.
The ECU detact there is more heat inside the engine, due to more air by pass the throtle valve direct go inside the engine, create more power and more heat, so the ECU first action is reduce the amount of fuel supply in order to reduce the heat, that is why people say this is the fuel saving system, in other word, this will damage the engine in the long period.
About the spark plug, first important thing is make sure the lenght is same as the original spark plug, if not, change it back immediately, diffrend spark plug model have diffrend lenght.
One of my customer is a live sample, the spark plug he use is longer then the original one, we told him change it back to the original one, but he won't listen to us, and say "this is "XXX" brand racing spark plug you know, what you know about racing huh? @#$%^&* DO RE MI FA SO...." 3 month later, complain high fuel consumption, engine no power, oxygen sensor malfunction....after using back the original spark plug, problem soft. Why? the position of spark plug are diffrend now, so the fuel can't effectively be ignited, and causing problem above.
About the brake system, it is ok for now you have done, but if you are planing changing the brake caliper, please make sure two diffrend model are using the same brake master pump, if not, please change the brake caliper togher with the brake master pump (diffrend brake system, diffrend brake presure), and please service the brake caliper before installing to your car.
Last, about the suspension, the setting is base on you loh ^_^ you feel the setting is ok, then is ok ^_^. Hard to give you suggestion here, b'cause diffrend people have diffrend driving style ^_^.