Dual exhaust sounds really good.
It will cost more & add more weight.
Most will mistake it for a V-8 when idling.
Torque converter, a good brand one, 2400-2600 stall with lock-up.
Don't listen to the nae Sayers by saying 2400-2600 is too loose.
A good quality one will act just a like a low stall converter, until you get on it hard.
At that time of getting on it hard, the RPM's will go up & act like a higher stall converter & really help with acceleration.
Having that type stall on your converter will really wake up the 0-60 MPH, 0-60 FT & still knock down good mileage because of the lock-up converter.
My Moms stock 1999 3.8 Liter Olds Intrigue torque converter has a stock brake stall of 2600 RPM, flash stall is actually higher.
Works just like a low stall converter & still get great mileage.
Now, that being said, if you do not want being focused on acceleration all that much, minimum stall of 2100-2200 RPM range @ the absolute minimum.
I just recently replaced my stock 1400 stall converter to a stock Corvette converter "2100" stall & I am really glad I did, it made a big difference in how my Silverado accelerates & did not affect the mileage one bit.
Just for reference my Truck has a 4L60E trans with the lousy first to second gear spacing. It is horrible how the RPMs just drop so low when shifting into second gear & my engine puts out 350 ft lbs of torque "Crankshaft rating" It's a long labor just to get through 2nd gear.
You mentioned about a catalytic converter, I asked about getting one for my 69 Camaro (does not require smog check)from an Ebay member to install & he stated he cannot sell to Ca. residents, & here I am thinking about cleaning up my emissions from my Camaro for the same reasons you want one, the smell.
This is the one I want to get for my 4" single exhaust.
http://www.ebay.com/itm/MBS-100-CPSI-5-B...=item5d506d0a9aJust remember, adding a catalytic converter is like adding a muffler, so IMO, I would get a straight through designed muffler along with your catalytic converter.
That is all for now.
