Worm gear clamps are weak and you can't torque them very much before they strip or break loose; these are not good on turbo/supercharged engines. They are good for intakes and such with low psi/vacuum.
They are not required...just a safe upgrade when you plan on increasing boost or if you want to mod your car the right way. Its like they say, your engine is as strong as your weakest link. A lot of people break down because of blown off intercooling pipes (FMIC, EVOs, STi, SRT-4, etc.). These clamps resolve this. We use these in aerospace applications (Shuttle), even when we are only pressurizing to 2-3 psi or even ambient.
They call them T-clamps because there is a bolt and nut in the shape of a "T" and the band clamp is looped on this bolt....
Check out the link on the post above and look at the bolt that runs across the top of the clamp.
