Side mounted intercooler - is a charge air cooler, a heat exchange device that's typically air-to-air or air-to-liquid type. Used for all types of forced induction internal combustion engines such as turbocharged and supercharged applications. A Side Mounted Intercooler (SMIC) is typically placed in-front of one of the front wheel wells as a direct result of space limitations. They're generally smaller in size and used in tandem to achieve the similar results of a TMIC / FMIC.
The theory behind an intercooler is it allows for improved volumetric efficiency by increasing intake charged air density through cooling (isobaric, constant pressure) by removing the heat of compression that occurs in any gas when its pressure or density is increased. Cooler charge air = more power generated!