NST Overdrive Pulley set compared to URD 2.8" S/C pulley

NST claims (dyno sheet to prove it) that their overdrive pulley set for the 2005+ supercharged tacoma's and xrunners will net 1.5psi increase in boost and a total of 341WHP. URD has the 2.8" S/C pulley that they claim will add 1.5 to 2psi of boost. My questions:

1. Since the urd pulley claims the same amount of boost will it increase your HP the same?

2. What would be the benifit to spending approx. $500.00 on the NST pulley kit instead of the $100.00 for the URD pulley?

3. Is it true that the aluminum lightweight pulleys will ease the stress on your engine at a constant speed compared to the stock steel pulleys, giving you more life out of your engine in the long term?

Thanks for the help.