1 - The new vitz with 1KR-FE 1000cc 3-cyl engine comes with a CVT.
2 - The oil that has to be put in the CVT by toyota is ATF-WS which is NOT available in Pakistan as of yet as per my knowledge. ATF-IV is NOT good for CVTS and mind it sir, it really isn't.
3 - ATF-WS has a CHECKING interval at 100,000 miles. that is about 160000 km. I also have a vitz 2005 which is well above 80,000 km now. Nothing has happened to the transmission. Although I will be changing its oil pretty soon and I will be using the CVT-F by Honda. Which is used in Honda City.
The best way to check if your car has a CVT or 4-SP AUTO is to floor your car and hear the engine noise.
If the engine stays at the same RPMs during acceleration its a CVT.
If the engine's RPM increase like a normal car and after a gear change which you would feel with a 4sp transmission the engines rpm would come down and the cycle continues. until you're in 4th gear. Which is not the case with CVTs, with a CVT transmission you'll hear the engine screamingggggggggg till you let lose your foot from the pedal.
Check this link for a very good flash video on cvt vs normal automatic trans:
HowStuffWorks "Cars with CVTs"
REGARDING THE CAT convertor:
Please make sure that you go to a good place (silencer wala). Make him remove the cat converter cylinder, there is an o2 sensor on the cylinder as well make sure he disconnects it before he starts welding and cutting. Make him destroy the CAT (ceramic grill looking thing inside the cylinder) completely and check the cylinder before fitting it back in.
My guy didn't empty the cylinder fully and some pieces of the CAT ruined the muffler at the back, make sure this doesn't happen with you.
Hope this helps.