The assumption in this question is that car loans and leases always lower your FICO credit scores, which isn’t necessarily the case. In fact, if you pay your car loan on time every month, it's likely that your car loan is actually helping your credit scores since a car loan diversifies your credit accounts. Account diversity is one of the five criteria that FICO takes into account when calculating your credit scores. So as long as you have a positive payment history on your car loan, it's likely that it's contributing as a positive factor in your credit scores.
Having said that, a car lease does not have any different impact to your credit score than a car loan does.