I dont think it will be all that much laggier. Call it the laggiest stock appearing turbo, but compared to a T3 frame or higher, I would still consider it NOT laggy. I really dont think you would ever notice the tinny extra lag compared to the 16g.. Or the 20g
But to me the only reason to use this turbo or a 16g is for the stock looking appeal. Obviously price is not a concern. So why not go for the most lb/m.
There are lots of other turbos that will net you more power at the same spool speed for that cost. Or even less.