Where to get performance parts for a H23 dohc vtec?

I have a H23 dohc vtec that is not a Frankenstein it is a true jdm blue top H23 dohc vtec from the si-r accord sold in Europe. Please I am looking for more horsepower from the civic I put this motor in. I'm not saying its not already fast just I know it can get faster. So I'd you know where I can find these parts please tell me the website. Thank you in advance for your help.