best mod/ upgrade under $1500

[renzop]

It depends on what you want to do with the car -

Performance - Short shift kit
Handling - front and rear sway bars
Looks - rear spoiler or lowering springs
Electronics - Aux input for an MP3 player or replace head unit with fancy GPS/Radio/CD like an Alpine
Maintenance - Why not spend the money on some preventive maintenance? Oil and filter change, brake fluid flush, coolant flush, AOS, MAF, AC service, suspension bushings, RMS, IMS

[crios]

I agree with these two, especially if you are a DIY guy.

Handling - front and rear sway bars
Looks - rear spoiler or lowering springs

It would actually be best if you could provide some pics of your car to give us some more ideas.

For a cheap mod, see my favorite one, easy on an 03.

DIY Exhaust Mod – Gain of 10+ HP!!!

[schnellman]

Driving a Porsche well takes training. Learn to drive your new car first. Only after you have owned a Porsche for awhile will you be able to decide what mods are best for you.