HOLDEN appears to have left few stones unturned when it came to the final, VZ facelift of its top-selling Commodore before it’s replaced by VE in 2006.

For while a superb new DOHC V6 receives top billing, some subtle under-bonnet changes have also made its V8 sports sedan flagship faster, smarter and more refined.

Not so subtle, however, are the new-look SS Commodore’s front quarter "speed vents", which further differentiate the fastest four-door Commodore from its new SV6 sibling on one side and a more powerful, upcoming Monaro on the other.

Of course, SS fans will applaud the now obligatory power and torque increase – this time an extra five points on both counts - to 250kW at 5600rpm and 470Nm of torque at 4800rpm, giving SS a new level of V8 performance and a specification shared only with the stripped out SV8 and top-shelf long-wheelbase Caprice.

Achieved via a Pontiac GTO-style, larger 95mm cold air intake, new exhaust and revised ECU software, the revised power and torque maps now see Holden’s most powerful iteration of the 5.7-litre Gen III pushrod V8 deliver more than 44kW per litre, or as much as the first Chev-powered HSV ClubSport released in 1999.

More importantly, SS is once again lineball for engine performance with its most direct rival in Ford’s XR8 (which produces 260kW and 500Nm from its 5.4-litre DOHC V8) given, as Holden is at pains to point out, that Holden measures all its performance figures in the more widely recognised ECE format rather than the more generous DIN measurement favoured by Ford.

Importantly, too, however, is a new electronic throttle, which offers perhaps even more real-world advantages than the higher peak output figures in terms of responsiveness, refinement and durability.

Making the most of these V8 engine updates is shorter new final drive gearing for SS’s otherwise unchanged T56 Tremec six-speed manual, which now dispenses with its ridiculously tall 3.46:1 diff ratio and swaps it for a lower, HSV-style 3.73:1 ratio.

Combined with the 1645kg VZ SS’s slightly better 6.62kg-per-kW power-to-weight ratio, the shorter gearing gives manual SS buyers greater launch feel while impacting only marginally on fuel economy.

SS automatics don’t miss out either, receiving a new torque converter with 13 times greater electronic smarts, plus a new hydraulic controller aimer at delivering smoother, less shocking shifts.

While SS and all V8 VZs, for that matter, miss out on the new V6 engine management system’s ESP electronic stability control (which also brings cornering brake control, electronic brake assist and upgraded ABS), its basic traction control system is also revises, offering a higher intervention threshold and unobtrusive activation instead of the previous system’s disconcerting pedal push-back.

SS also benefits from steering tweaks across the VZ Commodore range, which include a different front anti-roll bar pickup point (now ball-jointed, not rubber bushed) which reduces both its mass and bar crank length by 40mm to "increase the range of mild understeer at low to mid lateral G-forces".

Cosmetically, apart from the new fender vents - which represents the only sheetmetal change on VZ but actually don’t vent anything and simply house the clear side repeater lenses - SS also gets a the new, more heavily ridged VZ bonnet, more aggressive front bumper with larger airdam, larger Holden Lion badge and more compact black-bezelled projector headlights sans the current SS’s "bull’s eye" parking lights.

New, faster-looking 18-inch alloys complete the VZ SS picture, along with a revised rear spoiler, dark, Monaro-style circular-theme tail-lights, chrome tailpipe and the availability of Monaro’s Impulse Blue paint.

Inside, SS simply scores a lidded console at the top of its centre dash console.

Like all VZs, SS gets mechanical brake assist and the electronic brake-force distribution technology borrowed from the Cross Trac AWD system introduced in Adventra.

Apart from BA and EBD, SS continues to offer as standard: ABS, twin front and front side airbags, limited-slip rear diff, FE2 sports suspension, fog lights, body-coloured mirrors, , sports leather-wrap steering wheel, cruise control, auto headlights, trip computer, alloy pedal covers, six-CD 80-watt six-speaker audio system, exclusive power sports seats, exclusive s atin chrome door handles, exclusive "steel" dash fascia, air-conditioning and power windows/mirrors.

Holden predicts it will sell around 400 SS variants per month – around double the number of SV8s it expects to shift and half the number of sales it forecasts for SV6, manual versions of which are expected to comprise a substantially larger 50 per cent.

SS pricing rises $500 to $50,990 for both auto and manual variants, while SS wagon is discontinued.