Hi there guys, I'm new here hehe
I own a Celica 05 GT-S (2ZZ-GE) and I want to improve its performance. Let's just put turbo or swap engine aside, coz I will never afford that
Let's say I want to do minor performance boost, such as exhaust, header, porting polish, and piggyback maybe. Which one should I do first? What step did I miss? Maybe there's something I should do between exhaust mods and porting polish, tell me because I'm new in performance mods (before, I did some eksterior mods, not performance LOL).
I want to boost low RPM acceleration, since I think the low RPM sucks.. The engine only good on 5000+ RPM

Say, what should I do? Which header should I use, 4-2-1 or 4-1?
What is the size of the exhaust for Celica? And also, maybe a brand suggestion on exhaust or header will be much useful
One more thing, my Celica's speedometer's limited to 180 (original from Japan, I'm Asian btw ). Do you know how can I increase the limiter? Coz it sucks you know, I once raced my friend, at first I won but when I reached 180 I can't accelerate more, and my friend's car can reach 200+ and I lost
I have bad English so pleaaase forgive me if some grammar are wrong LOL.
Thankie