[Brandoe91]

227hp seems high for a non built or boosted 1MZ. Do you have a scan or pic of dyno?

As for mods for a N/A setup

Obx headers and y pipe.
Safc II (if you want to tune for better numbers)
Injen Short Ram intake with cold air extension

For the cat, go with a reputable brand like magnaflow and make sure it's 3inch inlet/outlet to match you current Lukey setup.

Post up some pics of the car and introduce her to the community.