I'd like to chime in my experiences on my turbo GO 5 ports ... I used to run a c6 until it ran without a filter. I put a GO 5 port with JP1 and since then it gives up nothing on the bottom and top to my C6 in my truggy. I have 5 gallons on mine now with still great compression(changed conrod at 3 gallons per Russell's recommendation) Also running odonnel 30% with an extra shim (I used a 0.1 shim from my C6, but my 2nd engine came with a free extra shim from racefactor) I even had an issue (caused by me ) and Russ took care of me. I used to be an engine "snob" and only ran italian mills after several bad experiences with SH/STS engines, but try a GO 'cuz the quality is there... Just because it's not italian and without a >$400 tag doesn't mean it can't keep up with the best of them.

PS Here's my personal pipe experiences with a 5 port
JP1 Great bottom Decent top
JP2 good bottom great top
Dynamite 086 hardcoated(my favorite in my buggy) good bottom and even better top than jp2
JP3 slightly better bottom than jp2, but less than dynamite, top is a little better than the jp1, but not as good as the jp2/086

Arnold