Automotive scientists researching the evolutionary development of the Scion xB found evidence showing this little monster's gone through some serious changes in its very short existence. The first generation xB introduced to U.S. consumers in 2003 was found to be a mutated sibling of the Toyota bB, first introduced to the Japanese domestic market in 2000.

In 2005, the bB evolved in its native Japan - aspiring to be much more than a refrigerator on wheels - into a "car-shaped music player that incorporates youthful sensibilities," a quirky description used by Toyota. Whatever the meaning of that tagline, the bB has undergone significant exterior, interior and drivetrain transformations on the assembly line and further evolution in the able hands of Japan's own Blitz Co., Ltd., the parent of U.S.-based Blitz Performance Sales, Inc.

If improved evolutionary fitness guarantees the survival of the species, as proposed by Darwin's theory of natural selection, then the Blitz bB will certainly be regarded as the champion of its kind. Undeveloped, the second generation bB comes equipped with either a 1.5 liter (109 hp) or a 1.3 liter (92 hp) 16-valve VVT-i four-cylinder engine, not nearly enough to impress the sophisticated urban female. Thanks to the genetic engineers at Blitz, this offspring received some desirable traits that make this specimen different from the others.

Beneath its sinister exterior is an even more menacing supercharged four-cylinder engine, which greatly improves the displacement to output efficiency by converting kinetic energy from engine rotation into thermal energy released during combustion. Simply put, some of the engine's power is converted to create a more powerful internal explosion, which, through the pistons and connecting rods, causes the crankshaft to turn more forcefully.

Toyota provided the engineers at Blitz with a solid platform for producing more power. This 2006 bB came equipped with the 1.5L, 3SZ-VE engine, a relatively new engine family produced by Daihatsu of all companies, which offers a cast-iron block in lieu of the Scion xB's aluminum block. Although heavier, the cast-iron block is better suited for forced induction since the volumetric increase following combustion is less likely to have damaging effects on the stronger cylinder walls. The bore and stroke measures 72mm x 91.8mm respectively, contributing to a relatively high compression ratio of 10.0:1, somewhat of a disadvantage when considering something that'll ultimately be force-fed. In general, a compression ratio of 9.5:1 or lower is more conducive to supercharged and turbocharged applications because it allows for higher boost pressures with a reduced likelihood of detonation. However, changing the compression ratio would require complete reconfiguration of the bB's bottom end, something the casual tuner would likely avoid. Instead, Blitz uses a Roots-style positive displacement supercharger dubbed Compressor System C7, still in the R&D phase for the bB, which takes into account the higher compression ratio and delivers a lower and safer boost pressure. Blitz engineers optimized the performance of the forced air induction on both the intake and exhaust sides by adapting some of their most respected products to this new system. Now is a good time to mention what's in store for the 2008 U.S.-spec xB - 55 more horsepower and an optional sequential shifting automatic transmission to be specific. The tC's 2.4L engine will be lent out to the wider, longer and albeit heavier xB. One can only wonder what Blitz will make of this.