how to upgrade my integra on acuraworld?

hello, i’m getting an acura integra da9 ls passed down to me from my brother with 80k miles he has it stock except for an exhaust and cat with new cool air intake I was wondering in my price range of 3,500$ what i can do to it without removing the stock transmission (automatic) I can’t remove the trans bc it’s my first car and my parents don’t want me riding a manual until i make it to college so i’m open to anything that’ll boost performance besides that i’m also somewhat new to cars but my brother is teaching me some but he also said that reddit and car forms are the best for learners thanks on acuraworld
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