Question about wheels offset and performance
 

I currently have an 08' Boxster with 18"wheels. Wanted to get some 19"aftermarket wheels online. The guideline says 8.5x19 ET50 front and 10x19 ET52 rear. The wheels are perfect for front but the rear is 10x19 with offset 60 or 42. The guy on the phone says it is a matter of preference. The 60 would be in the fender and the 42 would stick out giving a more agressive look. Is this true? Would driving performcance be affected by either one? Which would you choose? Do I need to get spacers?
Thanks:confused: