When I got the 7 port Go, I tore it down. I didnt have any shavings at all in the motor, didnt have any worms in the HSN or LSN either. I seal my engines before I ever start them so I can not comment on leaks. I know that mine doesnt have any airleaks after being sealed.
There is a 100+ page thread on Sgrid about the Go Tech engine line. Of all the praises there are only 2 people who had any type of problem. Both where a leaky pinch bolt. 1 was sent back to Russel at racefactory who repaired the carb tuned it then sent it back. The other one was sealed and was fine.
One of the nice things with the Go Techs, is Russel the US distributer does a QC check on all the engines he gets in. And if for any reason the engine doesnt perform you can send it to him and he will get it fixed. Hes also active on the sgrid site helping with tuning issues people have. Tuneing issues not due to a problematic carb just people needing help.
Another nice feature is the contigency program, if you fly his sticker on your car. Go to a race with 50 or more entries and make the A-Main he will send you an engine for free. If you win the B-Main you get 50% off your next purchace.
Did I mention parts to rebuild the motor are cheap? Conrod for 20.00 Piston and sleeve for 60.00 Case for 30.00 crank for 60.00. Carb slide for 7.00 whole carb for 30.00.
They also run well on cheap pipes, o83 for the 5 port and the o53 on the 7 port. Or you can get abit more power with the werks 2013 plus the nice raspy tune it has.
Im glad I took the plunge and tried one, I cant see my self buying any other motor ever again.
BTW for the 199.99 for the 5 port or 209.99 for the 7 port you get 2 plugs that are actually quality plugs. Thats a 12.00 gift for buying thier motors. Unless you get the Turbo versions, they dont come with plugs.
Just so you know, money isnt an issue for me when buying gear. So cost wasnt really an issue, there were to many praises about these engines and I had to try them. Glad I did.