THERE was a time when Italian cars were excused for a myriad of faults and idiosyncrasies simply because they were Italian. Unrelenting suspension, tortuous ergonomics and frequent lapses of reliability were thought to be the price one paid for owning a vehicle with a genuine, hot-blooded Italian heart. Fortunately for motoring enthusiasts, and for the Italian manufacturers themselves, times have changed. Reacting to the ever-growing level of quality, efficiency and sophistication of modern-day products, particularly those from Japan, companies like Milan's Alfa Romeo have responded with a new generation of Italian contenders that are accounting well for themselves in today's highly competitive marketplace. A prime example is the Alfa 155 four-door sedan. Replacing the outdated rear-wheel drive model 75, the new offering is a mid-range, transverse-engined front-wheel-drive sport sedan aimed directly at the young family men and women who want a little dash, zip and Italian flair in their motoring. The 155 is available only with a manual five-speed transmission, which may somewhat limit its appeal in the snarls of bumper-to-bumper Hongkong, but it definitely fills a niche. Just over 30 have been sold since its local introduction last November. The official name for the new sedan is the Alfa 155 Twin Spark, denoting the dual ignition and two spark plugs atop each of the four cylinders of the 1955 cc engine. Alfa engineers claim the system boosts engine efficiency and performance as well as promoting lower fuel consumption. Ignition and fuel supply are controlled by Alfa Motronic Integrated electronics, a sophisticated little black box that ensures peak performance from curbside idle to the 6500 rpm redline. The potent little 143 bhp poweplant sports dual camshafts and something Alfa calls a ''phase-variator'' which it says delivers optimum torque all the way from the basement to the attic on the power curve. Body-styling, although somewhat chunky in the rear sections, gives off a pleasingly aggressive air of purpose which is enhanced by well-drawn longitudinal contour lines and trim. The front end is classic Alfa Romeo. The famous Alfa shield nestles attractively in a wafer-thin grill. This functional and attractive leading edge cleanly parts the air while the overall body flow produces an impressive drag coefficient of only 0.29. Inside, the 155 is also well executed. Plush, comfortable seating with good lateral support is done in subtle yet sporty two-tone grey. There is ample leg and headroom front and rear, and the driver's seat is fully adjustable, including a lumbar support knob. All controls for windows, locks, mirrors and the optional sunroof are electronic and are well placed for easy access. Large and easily readable anti-glare analog instrumentation is complemented by a full arsenal of warning lights which tell you just about everything you need to know. The test vehicle was fitted with the optional ''auto climatic control'' air-conditioning - a digital, push button affair that is a breeze to use and keeps cabin temperature exactly where you want it. The flow of regulated air is efficiently directed throughout the compartment by multiple vents. Although the driving position is extremely comfortable, the adjustment of the padded three-spoke sport steering wheel lacks sufficient latitude to bring it to the close-to-vertical position favoured by some drivers, and the gearshift lever feels uncomfortably long, resulting in a rather long throw. Those minor irritations are, however, quickly forgotten the moment the smartly styled alloy wheels begin to roll. Under way, the 155 is pure delight, pulling like a train and taking to twists and turns like Madonna to a lingerie sale. There is a touch of understeer when going into tight corners, but the four-wheel independent suspension keeps the car upright with all four wheels squarely planted on the road surface. There is a demonic urge to keep one's foot firmly on the throttle, confident in the knowledge that the Alfa will sort it all out without undue fuss and bother. A simulated panic stop with hands off the wheel produced no surprises on the test car, which did not have ABS, but this is available as an option and is probably $10,000 well spent, considering the fact that this is a car that begs to be driven quickly at all times. Milan Motors can supply you with this most entertaining package for a base price of $228,000.