Though barely cohesive and questionably mixed, DJ Kurupt’s Summer Heat showcases the impressive (if somewhat random) talent Koch Records has assembled as major labels have jettisonned talent and shunned risk to save their sinking ships.  Indeed, Most of Summer Heat has already been released.  Heavy on decent work from Dipset (two songs each from Jim Jones and J.R. Writer) and D-Block, the gems here are surprises from veterans Def Squad (two Keith Murray tracks??!?) and KRS-One (“Act Like You Know,” with production from Marley Marl).