Throw out the dynamic output rating, it means nothing. Amp section distortion specs are GOOD. Power appears to be 150 watts into 8 before clipping.. The 4 ohm and 2 ohm rating show the power supply is not up to the task of doubling power into 4 ohms and then doubling again into 2 ohms, WHICH is what a properly desighed power supply should provide to the amp section. A lot of factors come into play when you see a rolloff of power into the lower ohm loads. Output devices having a limited current rating, transformer compromises, caps, etc.
A commercial application of any audio desigh is going to be a series of compromises, in essence it has to be to be a commercial success. Therein lies the niche for folks like Joe and his "take no prisoners " approach to his kits.He specs the very best components that he can reliably get, withthe result being what most of you have heard....exceptional sound quality. It does take a lot of effort on the implementation side to make it happen, but the cost savings are worth the effort and it's been shown time and again with the upfront engineering of Joe's, and some situationasl, and personal supervision it can be done by a wide spectrum of folks with varying degrees of expertise.
Sorry for not answering more of your question Jase, tuners and pre sections are still pretty foreign to me, but felt qualified to comment on the amp section...