if youre doing a spacer lift, it can depend on how many miles you have on the factory suspension. i have over 100k and with a 3/2 spacer lift my cv's are perfectly horizontal. the limit is usually about 3", but your best bet is to peruse the suspension faq thread. http://www.toyota-4runner.org/4th-gen-t4rs/102272-4th-gen-suspension-options-faq.html