so this is the first time i have ever had a powerful FWD car and i want to know how to reduce under steer as much as possible. any tips? would bigger tires help? stiffer or loose front suspension? what else should be done?

 

I'd start with an add on rear sway bar. I don't know what car you have or if you have done anything so far as far as suspension mods so I can't really comment further but check this link out as a general guide.

Massive List of Solutions to Understeer/Oversteer | The Smoking Tire

 

Powell or OTTP rear sway bar will make the car close to neutral.