Fuzzy, I will take a shot at some of the questions you have.
The world formula is not a TAG USA motor but does have an onboard electric starter. It is rated at 15 hp with a rev limiter set at 7100 rpm. The CIK has homologated this motor to their “world formula” for a world wide standard of 200cc, 15 hp, all under $1000 for the package including the motor, header, air filter, and clutch. TAG motors are approx. 28 hp and much faster but are more money to start off. With the rev limiter set at 7100 rpm, this will extend the life of the motor and I have heard that most motors will last for at least one racing season without falloff in power.
The advantages of this motor in addition to its low price is it will not require an expensive chassis to be competitive and you will not go through tires as quickly as the faster TAG karts.
The only disadvantage I can see is that it is slower than TAGs.
The WF is popular out east and on the west coast but has not caught on as much in the mountain region, at least not yet. I am hoping that a world formula class will form in the Denver area as well as CRE. I think it would be a very good entry level class for 2 age groups: JR2, 12-15 and SR, 15+. Some tracks offer this package for JR1 (8-12) with a restrictor plate.
Check out this link on Ekartingnews.com
http://www.ekartingnews.com/viewtopic.php?t=62858&PHPSESSID=4b235c1f84e078424fccc88c56d15598
It is about karters that wanted a less expensive package with much closer racing than the TAG classes in their area. Racing is relative, you only need to be faster than the others on the track to win the race.