What Are My Tuning Options For 2000 Civic Ex Coupe (Automatic)

I have a 2000 Civic EX and I'm looking into tuning it. I haven't found anything so far that will work, the closest one I found won't work with the manual trans. What are my tuning options for this car? I want to get the most out of it for the mods I'll be putting on, without spending too much on replacing the ECU. I'm still in school so I'm looking for cheaper options for tuning it but I'm open to anything.