The short answer to both of these questions is no. Discovery Live is intended as a tool for design exploration to allow for rapid testing of concepts. As such, the focus is on speed and ease of use.
The overall level of fidelity is directly dependent on the size of the model. If you have a specific area you wish to get more accurate results for, it is sometimes beneficial to isolate that portion of the geometry, either by performing a simulation on the individual component, or by cutting the model to isolate the specific area.
For more information on accuracy in Discovery Live, please refer to the following article, as well as the link at the end of this article concerning the relationship between GPUs and simulation results:
Discovery Verification and Benchmark Cases