Audi's original B5 Audi RS4 arrived in late 1999 and was only available as an Avant - unlike the regular S4. Lucky UK buyers got their hands on the car in 2000 and Audi went on to produce 6,030 units worldwide between 1999 and 2001.
The £46,500, 381hp RS4 used Cosworth-designed cylinder heads along with revised pistons, uprated con-rods and bigger intercoolers, as well as new intake and exhaust systems. With a capacity of 2,671cc, the 30-valve bi-turbo V6 came with a six-speed manual gearbox mated to Audi's default Quattro system - which enabled the RS4 estate to hit 62mph in just 4.9 seconds, on the way to a 162mph limited top speed. Serious performance for the day, despite weighing in at a chunky 1,620kg.
At tickover there is little sign of the power within, and at lower speeds the engine sounds ever-so-slightly grumpy - and there's a modicum of turbo lag. Push beyond 3,000rpm however and the RS4 is transformed, pulling like only an old-school turbo really can - past the 7,000rpm point where peak power is delivered.
Grip levels are huge too - which is probably just as well - and the steering, whilst lacking compared with lighter and more nimble cars of this era, still feels great against that in the much more modern B8 RS4. Those of a more practical mind may point out that the boot space is a wee bit smaller than in the later B7 or B8, but the overall driving experience is every bit as thrilling. And to have been one of those first lucky 532 UK buyers must have been fantastic.
With so few B5s originally sold though, finding a good one at decent price is becoming harder by the day. Prices start at £18,000 and rise to over £23,000 for the very best examples, but you're unlikely to see another one on the road. "The B5 is always going to be more special in my eyes than the B7 or B8 because of its exclusivity," explains Paul Farenden at Audi tuners Revo Technik. "Solely for the money I'd put it into a B5, although we might have already missed that boat!"
"Values for the first generation B5 have already started to rise to a similar level as those for the B8; and they are being bought as weekend fun cars, buy a demographic that are prepared to pay well for the right examples, and are likely to keep them for longer," confirms Robert Redman at trade gurus Glass's. And that's a view shared by Dougal Bennett at MRC Tuning "The B5 RS4 in a looked-after condition will always appreciate the most as it is the rarest car - there is something special about that first RS4." In the next few years expect B5 RS4 prices to follow the RS2.
So today, your biggest problem will actually be finding a good one - but if you do then be prepared to give it some love. For some it's already become too risky to use one as a daily driver, but there's no denying its legendary status.
Buy if: you fancy an exclusive, appreciating Audi that's a pleasure to drive
Don't buy if: you want a fast estate car you could drive every day
We found: 2000 Yellow RS4 Avant, full service history,103K miles, £21,950
Price Guide
Poor: Under £18,000
Good: £18,000 to £23,000
A1: £23,000+
Special Editions: There aren't any, but concours cars can fetch over £25,000