Redoing exhaust in So Cal...?

[kablooie]

I need to get my exhaust, from the manifold collectors rearwards, redone.

Coming from the collector, the OD is probably around 2-2.5 inches. Around where the passenger side wraps under and by the front shaft the pipe shrinks down to ~1 inch OD for about 2 inches along the length of the pipe!!! Both pipes come together and go into a cat converter (With 3 inch in/out openings, however the pipe going in/out is still 2-2.5 inches) and back to the Flowmaster and then one pipe exiting the vehicle (still ~2-2.5 inches).

What is the best size pipe to use from the collectors to the converter and then I'm assuming 3" is sufficient when the two pipes join and go into the converter and stay 3" all the way back.

Also, in Southern California, what would be a good price for getting this done?

Thanks! FYI the engine is pretty stock as far as I know.

 

[4X4HIGH]

I would come off the stock manifolds at 2.5" and make the Y pipe go into a 3" exhaust pipe into a hi-flo cat then into a free flowing muffler with a 3" tailpipe out the driver side behind the tire. A single exhaust will net you the most amount of low end torque over a true dual exhaust giving up some low end torque for more top end HP.