There are no readily available aftermarket parts for the V-6. You can possibly enhance the intake & exhaust but that's about it. We have a member here that has put tons of money into his V-6 and was somewhat successful. He did get a quarter mile speed of 100 MPH but the expense was enormous. In short, it's not worth the money.
Look, you're not going to get a whole lot of power with those, what you need is something bigger. I just got 4 more pieces in the mail today for my GT25 turbo install. Thats how you really get power. Forced induction. Just about everybody on the site has told me its a bad idea, but someone has to try it. (07 Sport V6) But this all is probably more money than most people would enjoy spending.