Sonar only could be the most run you can have with SH4!
And it is possible to use sonar augmented attacks to launch blind with periscope down or at depths greater than periscope depth.
Lagging passive sonar bearing is a function of computer speed I think. I run all manner of background processes and generally disrespect SH4s needs in the computer resources department. Limiting running processes and having a more modern computer than my Opteron 175/GeForce 7600GT would help in that regard.