so far l have a nice spoiler, underbody LED lights, tint, interior LED lights....what else should l get...i know l want an exhaust...(whats a good one?) l was thinking about some grilles...anyways...help me out here Thanks!

HKS Hi power exhausts.
lower the car, Black rims and brembo brakes with red calipers.
Limo grade tint.
Add carbon fiber body bits .
This will work best on Grey metallic, black or pearl white.
Give it a very mean and shamelessly aggressive look.

Punch in
''performance, scion tc, forums '' ,in google. These guys will have tried everything. Navigate to different forums and your answer will come better to you.
People will tell you what is best, but you will need to make the final judgement.and final payment.
Lawrence
carmatchpro.com

Use these Scion parts. Cold air induction, Super charger, Borla exhaust, Billet grill, tint, and 18'' Black wheels with Pirelli p-7 is to start. this would add about 5000.00 inatalled. you would get with also adding all synthetic fluids 270 Hp and about 290lb is of torque along with ZR tires for traction, and throaty whistle sound which is good sounding for any 4 cyl.

It sounds like you are just going for the looks; If Im right then you should look into getting the TRD tail lights, they look great. As for the exhaust, l would go with a flowmaster.

Check out Borla exhaust, a billet grill & maybe a vinyl.

http://customstore44.com/ I've ordered the SCION wind deflector vinyl from them. Check out what they have. You might find some cool stuff.

Consider, power coating the rims or upgrading them as mentioned above. Maybe a body kit? Get rid of those ugly ass red taillights though lol. Maybe a pair of carbon fiber ones or something with a blacked out housing. Did u replace the 194 bulbs in the headlights? Cheap & a nice accent. Injen Cold Air intake. Just trying to throw l ideas at you. Good luck.

Performance Upgrades:
Start with GReddy or HKS exhaust.i like Greddy bec. it is not angled
then put the Cold Air Intake - Injen is the best
then get megan Racing Header
Then get a Pulley = 5-6 hp

Body Upgrades:
AIT Racing Wide Body Kit
Tinted Windsheild
Lambo Doors or Vertical doors
Get projection headlights with exnon bulbs
APR performance wing spoiler
Kaminari Carbon fider hood
Tail lights