1. 1ZZ is 2" 2. 2ZZ is 2.25" 3. CES is 2.5" 2ZZ standard exhaust will be very good for a 1ZZ. With a 2ZZ, you wouldnt want to go any bigger than 2.5" unless you have done some serious modifications ie Turbo, S/C, or Stroking. CES is expensive (not really) because it fits first time, and the time and effort they have put into the muffler is the beauty of the system. You could strap any 2.5 inch pipe on the sportivo and it will gain a tiny bit of power. Any muffler, the car will kill your ears and get you defected. The CES, while it is loud i dont find it annoying at all. The cat stays the same, hence why the CES is a cat-back. no point changing the cat, its fine already. Basically, you wont find a muffler to suit your needs on a sportivo. Unless your willing to spend over 1k to pay for the R + D, and even then its better to go with the CES. Also... standard exhaust is fine... do the CAI first.