It's just a matter of how well you want it to work. I ran those shocks up until last year. The car would avg 1.38-1.42 60ft usually. Put afco dbl's on the rear & it averages 1.30-1.34 now. Best 60 was 1.27 where last year was 1.35. Still have 10 year old 90/10's up front. They will get afco's when the budget allows.