I believe these engines are now going to be distributed by RC Disco
Glen - it's Pete from Answer RC who's bringing these in

I've got something a bit special here that was delivered yesterday that I'm doing a review on - it's the Massive Mods (Australian Go distributor) modified version of the 5 port, known as the MG66. It's got all the Titanium Nitride coated parts of the engines in the pic above. I've stripped it down and taken some piccies, but need to write up what I think so far. Am hoping to run it in tomorrow and race it at Herts - may run 2 classes just so I can play with this motor in the buggy.
Also of VERY great interest to people who think OS P3 plugs are too pricey - the Go plug (T3) will be available very soon at a very reasonable price

In heat range it's somewhere between P3 and P4, which baring in mind I can't tell the difference in how my Speeds run with either plug in, should make it a direct swap for the OS plug.
Brian - there wasn't much wrong with the previous Go engines that proper break-in didn't sort - quite a few people rushed it because the engines were cheap. The latest range are much more like the 3 Port R Go that came out early last year - a couple of pre-heated tanks on those would remove the mechanical pinch, much like an OS engine.
The break-in instructions for the MG66 are basically pre-heat it and get it running, lean the LSN till it runs clean-ish, get it on the ground and drive it. After 4 tanks it's ready for race tuning over the next 4 tanks - job done!
Go engines went through many developments over the last 3 years - the materials have been refined, even the porting was tweaked to pretty much the same spec as my mate Dean does to improve the way they run - don't let previous reports pre-judge these motors. At around £150 RRP with a combo option for an extra £35 these are seriously good value for money!!
Adrian