I contacted them earlier about how this setup performed, this is his reply.   
Dear mralex714,   
"Hi  there, best thing you get is gas mileage and easy, really easy  maintance, and inexpensive parts. Bike will perform as good as with the 4  carbs and you will get same top speed. But you gonna loose the  torkiness and fast response in the lower speed taht the 4 carbs give  you. Please let me know if you have more questions. 
JUAN     
- juan.fernandez"