just a few thoughts about the 5 port.

things used;
-LRP number 6 plug
-massive mods fuel
-option turbo head (i wish these were standard :? )
-extra copper .10mm shim mid way through race day
-JP3 pipe (jammin)
-ofna x1cr team kit

i ran it in, and had my first club day with this engine. after 50 or so minutes racing, it is still not yet broken in.

the engine does not come with enough headshims. MassiveMods brought this to my attention at the track after he realised it could use a bit of help from some extra shims (comes with the headbutton clearance and one copper shim) i added a copper shim to it (.10mm) and it helped the engine a bit, but would still probably need another silver shim as well.

these engines are very tight, and the lack of the shims makes the problem worse i think.

before you run them in, get either a silver and 2 copper shims and wack them in, or use the two shims from the OS engine (if you have one).

the 5 port go seems to be a excellent motor. i ran mine with a JP3 jammin pipe....don't beleive the hype! (or should i say bad press about this pipe) the jammin pipe is excellent with the GO 5 port engine. i also used a werks racing clutch with carbon shoes and the softest spring. worked awesome.

also, with the lrp 6 plug i had very good punch out of the corners, and it ran cool. the engine was still rich-ish though, yet responsive. (had that annoying tingy sound new engines not yet bedded in have, you know the noise.. sounds rough and high pitched when you take of a jump )

the GO ran at about 130 or 135 celcius possibly. my OS runs at 150 or so with a OS 3 plug

as a user, i am thinking of changing the conrod, the engien was just ridiculously, stpidly, annoyingly tight i must admit. After break in, it might be reccomended, or at least give it a thought to change the conrod. im not sure how comon this is in offroad, but in onroad, it is common practice witht he quicker guys to do this after break in. From what massive told me the conrods are pritty cheap though so it might be a good idea

finally!, (sh1t long post) the engine ran almost as quick as my OS (fully broken in), yet my GO is still untuned to race spek tune, and is still not totally broken in!! great engine. with the bits and peices you may want to get (ie turbo button, shims, and conrod) it probably comes to the same if not $20 less than a OS, but honestly, it's just as good, AND QUICKER.