At first I was vastly disappointed. The stock model could not fit two out of three of my modifications (cammo netting and vents) and I couldn't even upgrade to the long 75mm gun which the StuG mounted. I needed to grind 4000 experience in a tier VI tank practically helpless against tier VI mediums. I was not impressed. However, the matchmaker realized I was gimped and placed me in matches against a lot of tier IV and V tanks and soon I was upgrading the suspension and getting back to the StuG firepower. A few matches later and I mounted the PaK version of the short 88mm with the same beloved damage and penetration as the one on my VK3601 but with 25% faster firing time. Yeeha.
Speaking of ol' reliable, I have all the equipment unlocked for the beast including the bigger engine, so now I'm grinding the experience and credits for the next tank in the line, the infamous PzKpfw VI Tiger.