that will help you in GMAT CRs but i suggest to try GMAT CRs only coz they are designed to be done strictly in 2 mins. but lsat CRs are not designed to be solved in this much time, as per my exp.
However if u wanna improve ur general logic irrespective of the gmat point of view, u can definitely go for LSAT CRs.

Having taken the LSAT and studied for it (I'm in law school right now), I can tell you that even though you get 2 minutes per question on GMAT as opposed to a little over a minute per question on the LSAT, the GMAT critical reasoning is substantially easier than the LSAT's equivalent (the upper echelons of difficulty in both tests are probably similar, but the low and mid end of the LSAT is definitely harder).

LSAT has much more varied question types and chains of logic that are much more difficult to follow than the GMAT. I'd honestly say studying LSAT materials is a great resource. Most of these GMAT CR questions seem easy to me now when compared to what you have to reason out on the LSAT.