I've just switched from ported with Harvey up-pipe to tubular with Harvey up-pipe. The outcome depends on what power you are running, over 400 usual route is tubular, under ported.
To give an idea I gained almost 400rpm of spool going from de-cat up-pipe and std headers to Harvey up-pipe and ported headers. I got to 440bhp on that setup, I've just switched to tubular + Harvey up-pipe and I've lost out slightly on spool (200 rpm max) but am getting the same power with .1 bar less boost.
If you want more info let me know and I'll dig out the graphs.
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2005 Spec B 6MT - KiDO tuned (~270Bhp)
Custom exhaust - Cosworth filter - Samco Intake - Tints - Bilstein B8/B6 & STI springs - SuperPro ALK - Whiteline positive shift kit, rack mounts, rear adjustable camber bushes, front ARB mounts & strut brace, 20mm rear ARB with AVO mounts, - Hardrace Gearbox and pitch mounts - Prodrive PFF7's - Front Brembos - Kenwood CarPlay - 1/2 carbon grille - STI front splitter
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