For anyone who is interested. Just had a 2.5" Manta catback fitted - (SSMKHN0233) to replace stock exhaust on a stock motor. It is the "medium" exhaust with two straight through (with glass pack) hotdogs up front and a straight through (with glass pack) muffler at the rear. Seems to be well made and exhaust tips are nicely finished. Fitted by Brendon at Wanneroo Mufflers (WA) and he seems very knowledgeable and did a good job. Original Holden exhaust has no V8 sound whatsoever - ultra quiet. Sound inside ute at idle - 48dB. Sound outside ute measured 2.0m from exhaust tips at idle - 52dB. With Manta catback fitted, sound inside ute at idle - 51dB. Sound outside ute measured 2.0m from exhaust tips at idle - 65dB. So a bit louder than stock but not at all offensive. Importantly, although not much louder, it has a great V8 sound. Around town (<80 k.p.h.) I can hear the exhaust purring away from inside the ute with the windows up. On the open road (>100 k.p.h.) I can't hear the exhaust note at all when cruising. Can hear a mellow, but not loud note, when gunning it through the gears to get to 110 k.p.h. Cruising at 110 k.p.h. measures around 71dB inside the cabin and that's about the same as with the stock Holden (ultra quiet) exhaust). Seems that road/wind noise is probably responsible for the 71db, with exhaust note being below that threshold. Good because there is no drone. Not so good if you still want to hear your V8 on the open road. This is the exhaust that GMH should have fitted as standard. Could be too subtle for some but I wanted zero drone and a bit more burble and this one fits the bill.