Aston Martin is constantly finding gaps in its product line-up. Last month, it was the Virage; this month, it's the Vantage S, sitting between the V8 and V12 Vantages. Not halfway literally - it hasn't got a V10 or anything - but it does aim to up the standard V8's driver appeal.

To be fair to Aston, though, there's more to the S than is immediately obvious from the mildly tweaked looks. For starters, the S gets an entirely new seven-speed gearbox. This is now a robotised manual, rather than the normal V8's 6spd torque-converteror manual, and it's also air-cooled.

That doesn't sound significant. But it means Aston can get away with no oil pump - not only saving 16kg, but also reducing hydraulic pumping losses. The upshot of all that? It's a far more efficient system, so more of the engine power makes it through to the rear wheels. Clearly a good thing.

As it is, the S already has more power and torque than the ordinary Vantage - but only 10bhp and 16lb ft, so you can't exactly tell that the 0-60mph time has dropped by 0.2 seconds.

The whole car feels a lot sharper, though. The steering is so much more direct that the old car's is vague in comparison, and with the Sport button pressed, throttle response is ace. It needs driving hard to get the most from it. Take it easy, and the new gearbox pauses as it engages the next cog, causing the S to lurch, but go for a full bore upshift and the 'box bangs into the next ratio far faster and more smoothly.

Aston has also changed the front brakes, so they're larger, have gota floating-disc design and six-pot calipers. Which is a techy way ofsaying they don't fade as much now. Suspension alterations include a softer front anti-roll bar and squishier rear springs. Now this may sound counter-intuitive but it means the S now understeers less.

As with all Aston updates, the looks are subtly different, not radically altered - it simply gets a V12-style makeover to boost the aggression. Aston being Aston, the Vantage S hasn't turned into a Porsche 911 GT3 and ditched all the luxury toys in a quest to lose weight. A B&O stereo is available and aircon is standard - there's luxury here.

Which is a good thing. The S still doesn't have enough precision to take on its most track-focused rivals, so it needs a different USP - hardcore luxury. And at £102,500, it offers a good alternative to both the V8 and V12 Vantages. As with the Virage, the middle-of-the-road Aston makes the most sense.

Piers Ward

We like: New steering, aggressive looks
We don't like: Slow gearchange at lower speeds
The  verdict: A 911 GT3 offers more precision, but the S gets the Vantage much closer.
Performance: 0-62mph in 4.5secs, max 189mph, 21.9mpg
Tech: 4735cc, V8, RWD, 430bhp, 362lb ft, 1610kg, 299g/km CO2
Tick this on the options list: Sports seats, £2,000
And avoid this: Boot-mounted umbrella, £150