SUMMARY of what I did. It may be useful for somebody else in a similar situation.

I looked at Doug Thorley suggested by 277000_yota and see it as too noisy.
My son paid quite a few tickets for having something similar on his car.
It looks like this is just a pipe, no muffler on it.

I looked at Gibson. I spoke to Gibson people.
They say their product is Dyno tested for each car its build. They guarantee performance gain on low rpm.
Reading between the lines I doubt that is the case without installing their headers also.
However, their product looks good and it is relatively inexpensive.
I believe this one is worth considering.

There are two part numbers available (for Gibson Swept Side Exhaust; there are other types) for MY T100:
Gibson part# 18806 aluminized; expected life about 3 to 4 years (in Mass) - cost $312.00 + ship;
Gibson part# 618806 stainless steel - lifetime, cost about ; $430.00
I have red many good customer opinions on this product; very view not too good; mostly due to installation issues.
I WAS READY TO GET SS 618806 BUT I was told I'd have to WAIT at least 2 weeks.
None of the places a called have them in stock. It looks like most of Gibson products are made to order.

Unfortunately for me I could not wait to weeks.
So, I decided to go with the Toyota stock; expected live 4 - 5 years.
I ordered Toyota part# 17430-62220 from partznet.com (Conicelli Parts Center in Pennsylvania) for $190.36 plus $16.73 shipping. Its about $55.00 savings compare to local dealers.
Guess what. Next day Conicelli emailed order cancellation stating that it is to difficult to ship (costly). Same story went with everybody else.

So, wanted or not, I had to talk to local dealership.
I ordered my parts: (usually for next day delivery)
17430-62220 pipe assy, exhaust
90917-06057 gasket, exhaust pipe ($11.57 donut gasket, not chip but its a must)
90105-10388 bolt, washer based 2ea

I'm about to pay when the sales rep says: By the way there is a lifetime warranty if installed by us.
So, I stopped my order talked to the service advisor and placed a repair order.
Repair order calls for 1-hour labor on this project, about $95.00 in this particular place.
They agreed to lower my time since old exhaust was already removed.
My parts arrived next day and the job was performed without any problems.

My total is $327.60. Labor part 43.50.
AND HARD TO BELIEVE:
My service advisor STATED few times:
ôLife time warranty is for PARTS AND LABOR; as long as I have original receipt.ö
IN translation, I understand that as long as I own this truck I get new exhaust from ANY Toyota dealer in USA. For NO or very few bucks.

I wonder how many times I will use this receipt??
If that is the case this looks like really good deal for additional about $45.00.


The highlight of my day at the dealership:
I was leaving when some old lady started yelling:
"YOU SHMUCKS! 70 BUCKS FOR OIL CHANGE!!??"

I was laughing all the way back home.
O well, the owners have to pay for multimillion dollars new, European style building, somehow.


Thanks