I'm guessing that comparing them head to head, the 2.6H will probably slightly outperform the MP1900....but that's not to say it’s because the Kenne Bell has designed a vastly superior blower....quite the opposite actually. In this case (and in most cases when Kenne Bell compares their units to the competition) it comes down to sheer size. The MP1900 is a good bit smaller than the 2.6H displacement wise (1.9L vs. 2.6L) and as such isn’t capable of moving the same volume of air into the engine. That being said, testing of Eaton TVS (Twin Vortices Series) has shown that their efficiency levels surpass that of the famed "Twin Screw" design, so it would stand to reason if the two were of the same displacement, the TVS would be the clear victor in the match up.
Regardless, the MP1900 is still more than 600hp capable and at $999 for the MP1900 upgrade, it certainly seems like more bang for the buck compared to the $1,999 upgrade for the 2.6H (not including the cost of additional supporting components). Besides, if you really must have a more capable unit, the TVS also comes in an MP2300 configuration. Although you might want to check with TT for its compatibility with their kit?
Check this link out if you want a little bit better insight as to what the TVS Eaton’s offer as far as design and performance!
MySpaceTV Videos: StangTV.com - Eaton Superchargers at SEMA 2007 by StangTV
As for hood clearance....I can't seen the MP1900 being any larger physically than the M112 that comes standard in the kit. So if the M112 will clear, I'm sure the MP1900 will as well? It couldn't hurt for you to contact Tork Tech directly to find out for certain though?