I'll admit that I was a little unprepared prior to setting off for the first time in the new EX30dBut this time, and without apology, all I knew was that the new three-litre diesel EX30d was about to go on sale alongside the petrol V6 EX37, that it was a well-equipped all-wheel drive compact crossover costing about £37,000, and that was about it. However, even if I had been aware in advance of all the above and more, I'd still have been both surprised and impressed by the fine driving experience the EX30d offers.The model's refined three-litre V6 feeds 232bhp and a substantial 406lb/ft through a seven-speed auto and an "intelligent" all-wheel drive system with Active Torque Distribution. Those figures would suggest that, though being some 81bhp down on the EX37, the EX30d is far from underpowered, and with a 141lb/ft torque advantage the diesel's punchy acceleration is in a different league from what you might expect from a straight-laced luxury compact crossover, or a car without any obvious visual clues to its performance potential.For the record the EX30d figures are 0-62 in 7.9 seconds with a 137mph top speed. Impressive enough, but it's the availability and accessibility of good power that impresses most, and all this without having to resort to the transmission's slick manual mode.Though a 4x4 crossover that offers the all-important commanding driving position, the EX conceals its slightly higher centre of gravity well. The lightweight, largely alloy suspension systems (double wishbone front, multilink rear, with Dual Flow Path dampers no less) ensures a suitably comfy ride while also maintaining good body control, even when barrelling through bumpy B-road corners.The EXd also steers accurately, grips tenaciously, is well-balanced and requires some pretty heavy-handed/lead-footed driving before the ESP warning light flickers, at least in the dry. I've little doubt that the benefits of Infiniti's ATTESA E-TS system (Advanced Total Traction Engineering System for All Electronic Torque Split – who invents these increasingly ludicrous acronyms?) would be more apparent in slippery conditions, but in short the EX generally imparts far more the feel and character of a sporty saloon than a creature comfort-laden compact crossover.Speaking of creature comforts, there's no shortage here, but this you would expect of the top spec EX from Nissan's luxury brand. I'll spare you the tedium of listing the 50 or more standard gizmos, gadgets and other features, but a few are worthy of mention, if not to vindicate this GT Premium model's not inconsiderable £42,500 on-the-road price (as tested): Lane Departure Warning/Prevention, Frontal Collision Warning, Intelligent Cruise Control, Intelligent Brake Assist, a high res touch screen display, an Around View Monitor with parking sensors (handy as rear visibility isn't an EX strong point), a 30GB HDD navigation with voice recognition, Michelin guides, speed camera warning (handy as speed is an EX strong point) and 3D Places of Interest, a CD/DVD reader with multi file format compatibility, a 10GB Music Box supported by the Gracenote database and Bluetooth/USB/iPod/iPhone connectivity.Sorry, that's more than a few, and I didn't mention the leather upholstery, Scratch Shield self-repairing paint or indeed my test car's optional (£615) 11-speaker Bose sound system, but I'm sure you get the picture.Inside there's ample space and comfort for front seat occupants, but the EX's sleek rear roofline (with attendant 0.33 coefficient of drag) doesn't render it ideal for the family of five that likes to pack the kitchen sink. There's ample headroom in the rear, but the EX isn't over-endowed with rear legroom or indeed load space, which is quoted at 340 litres (seatbacks up). And the steeply sloped tailgate would prove restrictive when attempting to load larger, non-deformable objects.Infiniti describes the EX as a coupé crossover, and so on no account should you mistake it for a cavernous estate. On the plus side there's a 45-litre underfloor compartment, an integrated coat hanger in the back of the driver's headrest and the powered, split-folding rear seat backrests can be remotely lowered or raised at the touch of a button.The EX30d line-up starts at £35,975 and it's reasonable to assume that anyone spending that or more is unlikely to be unduly concerned by incidentals such as its 33.2mpg combined figure (8.2mpg up on the EX37) or its 224g/km of CO2 (two tax bands lower than the 265g/km petrol EX). That said, there are some slightly less powerful diesel SUV rivals that fare slightly better on these counts, but they don't come with Infiniti's Total Ownership Experience, which, in the company's words, "puts the Infiniti owner first with VIP-type levels of service care".This includes a free pick-up and delivery service within a radius of 150 miles of the dealership, although if you don't happen to live or work within 150m of Infiniti's only two current outlets in Reading and central London, or the two due to open before 2011 in Birmingham and Glasgow, then that may not be too much of a draw. Engine 2993 cc, 6 cylinders Power 238 bhp @3750 rpm Torque 406 ib/ft @1750 rpm Transmission 7 speed semi-auto Fuel/CO2 33.2 mpg / 224 g/km Acceleration 0-62mph: 7.9sec Top speed 137 mph Price From £35442.00 approx Release date 01/04/2010