If the BLS range as a whole represents Cadillac's attempt to come to the people, this is the car within that range which starts heading back towards the company's historic position as a provider of special vehicles for the well-off. With 255bhp under the bonnet, the Sport Luxury is the most powerful BLS, it has the most highly-developed suspension, and it's the best-equipped. It also costs over £30,000, or more than half as much again as the entry-level turbo diesel we tested recently.£32,398, to be precise, if you go for the six-speed automatic transmission tested here (a six-speed manual is also available and £1400 cheaper). At this money and with this power output, the BLS Sport Luxury finds itself up against formidable opposition from Audi, BMW, Jaguar, Mercedes-Benz and Saab, the last of these being the company that actually builds the BLS, largely from components it uses in its own range. So how is the BLS meant to stack up against all that lot?It doesn't have what you might call a head start. I was only mildly impressed by the 1.9-litre turbo diesel (see road test), and reckoned that the best thing it had going for it was the badge; Cadillac is still, after all, quite an exotic name in the UK. But there are big differences between that car and the Sport Luxury, and they're all hinted at in the name.Sport, for example. This is the only BLS available with the 2.8-litre turbocharged V6 petrol engine - or you could say that the engine is available only with this trim level. Either way, there's not much doubt that it's a very effective unit. Maximum power, as already discussed, is 255bhp, and the maximum torque of 258lb/ft is produced from 1800-4500rpm. If you can't be bothered with figures, try this: put your foot down, and the BLS goes, almost regardless of what was happening when your foot was still up. Acceleration is hard, yet refined.Straightline speed isn't everything, of course. You have to harness the power somehow, and Cadillac has done that by fitting the Sport Luxury with an exclusive handling package. The suspension has been stiffened, the ride height is lower than that of every other BLS, and 225/45 tyres sit on 18" alloy wheels, the largest in the range.Unfortunately, it's not that effective. I drove the Sport Luxury on the same roads on the same day as the turbo diesel, and although the handling package coped with the higher speeds, it didn't do much else worth boasting about. The more expensive car doesn't feel any sportier than the much cheaper one, and the ride quality is several orders of magnitude worse. It's all rather unfortunate considering which car has the word Luxury in its title.Equipment levels are, of course, the highest in the range. The Sport Luxury gets a lot of items as standard which are optional on the Luxury and in some cases not available at all on the entry-level SE: a Bose sound system, a universal hands-free mobile phone adapter, bi-xenon headlamps and a visibility package consisting of dimming interior and door mirrors (the ones on the doors also fold) and rear parking sensors.Options on the Sport Luxury include a powered glass sunroof, Kenwood DVD navigation system (for which handsfree Bluetooth capability is another option) and metallic paint. Choose all of those and the cost of the car increases to just over £35,000. Even if you stick to the standard equipment, this is on the face of it quite an expensive machine, though you can spend far more on extras if you opt for one of the German rivals instead.At the same time - and I'm guessing on this one but I'm pretty sure I'm right - those German cars are surely likely to retain their value better than the BLS will, which turns the financial argument against the Cadillac once more. I'm left with the same conclusion I came to with the turbo diesel: the BLS Sport Luxury will succeed only if enough people are sufficiently impressed with the idea of an American badge to make all other considerations seem pointless. In this case, I'm not fully persuaded that they will be. Engine 2792 cc, 6 cylinders Power 255 bhp @5500 rpm Torque 258 ib/ft @1800 rpm Transmission 6 speed semi-auto Fuel/CO2 26.6 mpg / 259 g/km Acceleration 0-62mph: 7.1sec Top speed 152 mph Price From £31601.00 approx Release date 08/04/2006