There are many great engines out there, but you $$$$ will determine which is best for YOU. Without that in mind we can talk forever on what motor to get. There are many other posts on here that discuss this.
I have a jp fx for sale for 200$ It is a 3port. it has 10 tanks of fuel thur it. I had it in my RRR. Both of them are about a month old. If no one buys it , i will put it on ebay with my RRR this weekend. Email me if your interested.