It will obviously impact on your database performance and also functionality of vcenter as there are more metrics collected at all intervals and this generates a lot of data. But level 2 is not that bad. Do check the growth size and whether you will be able to accommodate the growth. I think level 3 and 4 are the ones which will cause more impact.
Abhilash B
LinkedIn : https://www.linkedin.com/in/abhilashhb/