Only Russian sub that I can play with some confidence is the Sierra (noiselvl 125). The rest are a pain and are very easily detected by nmy escorts and subs.
Only way (imho) to be competetive at a reasonable lvl is to alter the "SelfNoise=" setting inte appropriate vessel .txt file in the D:\Your game installation path\MODS\ColdWatersSovietCampaignRev1.01\ColdWate rs_Data\StreamingAssets\override\vessels
For example. Victor III is at SelfNoise=137, Los Angeles is at 115 and Narwhal at 105. Huge difference.
I play the Victor III and set SelfNoise to 125 which makes it (according to my skill lvl) competetive enough. Sure, somewhat harder than a fairly modern US sub (since hydrophones etc are worse as well) but that is how I want it.
Cheers