Dan Trent – I've met the greatest BMW M3 of all, and I cant have it

And then the other day BMW assembled some of the weird and wonderful side-projects, prototypes and might-have-beens as part of a celebration of the M3's 30^th anniversary, photographed them in glorious detail on an airbase somewhere in Germany and put together a simultaneously fascinating and yet deeply upsetting press pack on what had gone into them.

Upsetting? Yes. Because while the one-off E30 M3 pick-up that served as a factory hack until just four years ago was amusing some of the M3s BMW didn't make looked pretty damned cool. Like the M3 Compact with its stumpy wheelbase, 321hp straight-six and Kevlar-backed Recaros. It never made production but it wouldn't take a huge amount of effort to build something along those lines yourself or, failing that, the current M2 pretty much follows the same template, albeit carrying rather more weight than this car's 1,300kg.

So that one I can cope with. It's that M3 Touring that really plucks the heartstrings, doubly so because they built one, it still exists and it looks absolutely fabulous. To my mind the E46 M3 is the definitive blend of understated menace, daily luxury and a gloriously sharp, high-revving and powerful 343bhp straight-six M motor. I'd be happy with a coupe like the one a friend has just bought. I'd be even happier with this, had they ever built it as a production car.

The E46 Touring was always a pretty car anyway; with those flared rear arches and the quad exhausts it just looks rude and a perfect combination with the subtly M-enhanced front end with its bonnet bulge and side vents. It's even on the 18-inch wheels and showing a bit of sidewall, absolutely the discerning choice for any E46 M3 and proportionally perfect for the car. And, yes, from the interior pics it's clear this development mule was a manual too. Spot. On.

Reading the accompanying text is just heartbreaking though. In it Jakob Polschak, M division prototype builder of some 40 years standing, explains more. “This prototype allowed us to show that, from a purely technical standpoint at least, it was possible to integrate an M3 Touring into the ongoing production of the standard BMW 3 Series Touring with very little difficulty,” he says. Very little difficulty? So why not do it? “One important thing we needed to demonstrate was that the rear doors of the standard production model could be reworked to adapt them to the rear wheel arches without the need for new and expensive tools,” he goes on, the press pack saying the M3 Touring "required only minimal follow-up work" to fit the rest of the M parts and complete the package.

If it's that 'easy' I guess an enterprising man could buy an E46 Touring, an M3 donor car and set to work with the angle grinder and welding torch to come up with something representative. Word has it people have. But I don't want a DIY cut and shut, no matter how artfully done. I want an M3 Touring built by BMW. I realise this column is meant to be about cars I could buy, not ones I couldn't acquire for any amount of money. With this recent round of publicity this prototype has done its work though. How wide would the cheque book have to stretch to convince them it was time to pension it off to one very, very happy owner?