1yr old Yaris 5spd sedan S w/150,000+miles

[trini_per4mance]

I bought my Yaris 5spd sedan S on 8/2/06 for my job and 1yr later I have 150,000+ miles on it. The only thing that I have done to it maintenance wise, is 30 oil changes and spark plugs after 100,000 miles. I still haven't changed my accessory belt. Does anyone suggest that I change it? I get about 40mpg - 50mpg @ 50mph - 70mph. I only started modifying the engine after 140,000 miles. Mods include: Weapon R Secret Intake with a steel mesh filter instead of the Weapon R foam filter, Megan Headers, Dynomax Super Turbo Exhaust (kept the stock look), NST Crank Pulley, TRD Sway Bar, Tanabe Springs and Strut Brace, F1 Lights 16" Racing Wheels, 8000k HID's in the headlights and fog lights, Bellon Voltage Stabalizer, 2.5" Spinning Tornado, and Greddy Speed Cut Defencer. I must say, I think my yaris runs way better than the average yaris out there. For example on the highway I can keep up with an 07' Civic Si from 70mph to 110mph and after that, the Civic Si pulls away. That's 106hp vs 192hp. Not bad! I have yet to take my car to the 1/4 mile or 1/8 mile track. But most people that have driven in my car or seen my car run on the road, thinks it about a mid 15's car on the 1/4 mile. I'm open to suggestions and/or opinions.