The first Sierra's suffered from the same bugs most Soviet SSN's had. Sloppy workmanship and un-tested techniques were hallmarks of yards who's primary goal was to get boats into the water as fast as possible. It was hoped that flooding the water with subs would overwhelm the NATO whiz-kids in their technology-marvel boats. Embarrassing catches by NATO ASW units were a staple of Soviet submarine life. The worst one would be the Victor Class submarine that was "caught" in a US Navy destroyer's towed array and came within a mile or two of being dragged into American territorial waters (which would have resulted in a depth charging and forcing to the surface/capture). The red-faced Politburo pulled all attack boats in and re-thought their processes.
A focus on sound-silencing was carried out and the Russians experimented with quieter electronic equipment, slower speed and hull coatings. The Sierra's were little better than the American Sturgeon Class, but like the elderly Sturgeons, they were stealthy when they needed to be and sturdy enough to survive a scrap. By the time the final bugs were worked out, the Cold War was over and the Russians found themselves strapped for cash. The Sierra's were able to withstand years of financial neglect and when the new Russian republic ressurrected them, they were no worse for the wear. The current bunch are sturdy, effective machines and are probably the most capable fast attack submarines in the Russian inventory.
Our kit is the Dragon/DML "USS Benjamin Franklin versus Soviet Sierra" and the kit builds in little less than an hour including paint and decals. Fit problems? I doubt it. Accuracy? Not really. But there ya go. Decals came from the scrap box.