The spacer size is greatly dependent on your intentions. The 5mm spacers will net a 37mm offset, and allow for dropping in mild springs, like COBB, on stock diameter tires. Absolute flush for a 7" width wheel is 30mm. With 30mm, one is looking at coilovers with stock diameter tires. Shorter tires may allow Cobb springs, however likely with a loss of tread width. Get the 42mm's mounted up and we will go from there
.