all the kits are pretty much the same, so one is not particularly better than another. the main difference between vendors of these kits is the level of customer service. some members here have had great customer service from bgf, others not so much. i personally have a replacement engine that I bought from bgf over a year ago and is still running like a champ. its the best engine i have owned by far. i cant be 100% certain, but i do believe that the engine in the kit you showed comes with a wider front engine mount, which should fit your down tube just fine with no modification. I know my engine fit my frame because it has a wider mount.
