After second read of the site (look like they are based up my way in MN too)….
You also need to consider what you plan using it for, racing or just testing. It might not pass tech for most kart races, any oxygenates tend to make the digatron go nuts. I could be wrong but, afterall they do mention karting on their site but motors in karting start at 40BHPp/L and go to as much as 350! Thats a big range in specific output. Kart motors also tend to see very high rpms which combined with small bores generally require faster burn times and lower octanes.