Never had an issue with Goodyear motorhome tires. They lasted about 7 years on my motorhome and only changed them out due to age. There were no cracks and I store my RV outdoors.
I think his knowledge and wheel time racing the Kawi and being part of the development of the H2 is what makes me think he has an edge. They all do springs and they all modify the internal bypass tube or have there own. Plus I think going with him you can get the shock/spring set up tailored...
I would go with the springs are slightly better than other OEMs. I talked to Carson at the Sand Show about the shock work he does on the H2. I think I will go with Carson for shock work.
Superchargers are going to drink fuel. With the bigger stock tank I would still expect to get 120...