I would think if you are having dropouts and/or crackles and such, that these would be usually due to parameter values for things like ASIO Buffer Size, Driver Mode, Sample Rate, and Record Bit-Depth.
So after you get everything up and running, please post your values for all of the above, for Sonar, and for the audio interface, along with the Sonar-reported Latency values.
I usually recommend settings of: Audio interface - ASIO Buffer Size of 128, Sample Rate of 48 k, for Sonar: Sample Rate of 48 k, Driver Mode of ASIO, Record Bit-Depth of 24 bits.
The above settings are what I recommend as a starting point for recording. For Mixing, I suggest jacking the ASIO Buffer Size up to as high as 1024, which will allow more robust effects like Perfect Space or Boost 11 to have enough room to do what they do. Then, for the rest of time, you will switch ASIO Buffer Size back and forth - low for recording, and high for mixing/mastering. It's just the way it is.
Bob Bone