Part one in our series on how to be a millionaire starts with the basic groundwork. The first thing you must do is take a beautifully sculpted car, like the Porsche 928, close your eyes and chop the hell out of it. If you are expert like Lynx or b+b then you have a decent product, if not you get an old dog.

It appears that the more desirable a motor car becomes, the more people want to change it. The Porsche 911 has been hacked about and added to with particular verve and now the company's 928 is entering the fray. In future issues we shall be looking at various conversions but this month we take a peek at some topless models.

There are several American coachbuilders prepared to slice-up the flowing lines of the 928, but only a few in Europe. One is the German b+b company, but first we shall look at the latest offering from Lynx Engineering in Hastings.

We first fell upon the 928 back in May 1985 when it was in the early stages of 'destruction' and Lynx had just removed the roof. At the time we were covering one of their other convertibles, the Saab 900i, but were determined not to allow the Porsche to escape our attention. Later we photographed the Lynx Mercedes 500 SEC convertible, but still the 928 was not completed. Finally we received a call to come and see the finished article. The reason for such a lengthy build-up period is that it was their first attempt and represented the prototype for future Lynx 928 convertibles.

Back in May, the car was equipped with various torsional-strength measuring devices which illustrated the degree to which it twisted without its roof. It was fascinating to see sectional cuts through Porsche pillars and bodywork that revealed the internal make-up of the machine and once Lynx had established what sort of a difference the lack of roof made, they set about restoring rigidity. This involved fabricating box sections which run down the sills and are joined at each bulkhead. 

They have aimed for somewhere near 90% of the original car's rigidity and if the Saab conversion is anything to go by then the target should have been met. Next came the work on the rear end which necessitated new steel wings and a fabricated steel frame for the aluminium bootlid.

Other 928 convertibles have a flat rear deck but Lynx Engineering felt that the original lines should be retained and so attempted to follow the curve of the bonnet through to the back. This they achieved with hand-beaten panels but they had to produce four bootlids before they were happy with the curvature. The design is subsequently unique but with such a heavy look perhaps they wish they had opted for the simpler style.

Last May we were shown the experimental hood mechanism, which was made from bits of Meccano but illustrated the concept. This time the power hood was installed and operating which is fortunate because the car was due to be shipped back to its owner in the States within the week. It works by applying the handbrake and putting the automatic shifter into park before the button positioned under the steering column may be pressed and the roof raised, provided you have released three catches above the screen. 

The reason for this palaver is derived from a French woman who attempted to raise one of the company's power hoods while on the move, with dire effects. The top slowly lifts and folds back to rest behind the rear seats and must then be covered with a tonneau that is secured by press studs. An amount of boot space is lost because the owner wanted to retain the 2+2 capability. 

Hood-up, the Porsche 928 is classed, along with snails, as an acquired taste. The predominance of black creates very heavy styling, although the inside of the mohair hood is covered in grey cloth to make the interior seem more roomy despite no obvious loss of headroom. The American owner's penchant for black is rather a clumsy choice for Britain, but in the bright sunlight of New Jersey - The Garden State - the extraordinarily deep finish to the paintwork should look stunning. 

You may have noticed that the car was originally silver and Lynx applied several coats of gloss emulsion to everything in sight, including the wheels which could definitely do with alloy rims. Lynx themselves would not have finished the car in this way and are intending to fit the next convertible with a rear boot spoiler to alleviate the cumbersome rear styling, and some wider BBS wheels would look just dandy.

If you have got your own ideas then buy yourself a 928 for about 36 grand and get Lynx Engineering to carry out its conversion which costs £14,250 plus VAT. The Value Added Tax works out at a further whopping £2,137.50 but then you are free to style the car as you wish, lucky thing. Lynx Engineering is on 0424 51277.

Now, the company that prompted the Lynx work is the b+b company which had been customising Porsches long before it became fashionable for everyone to do it. In fact. numerous conversions to an array of German vehicles have provoked controversy for years and led to manufacturers and Government Ministries seeking the help of the company's founder and mentor, Rainer Buchmann.

The 928 was initially available as a targa which has the same flat rear deck as the convertible but has a proper back-window panel to produce a definite two-seater and not some wishy-washy 2+2 device. The central T section of the targa roof interestingly houses the hi-fi which one customer specified to be so powerful that when the radio was on and the engine idling, the headlights would flicker. Though this was obviously rectified later. 

The true convertible has that flat rear deck which inspired the hump-back Lynx 928. Going by German prices, which you must if you want one because b + b has no UK agent, a basic Porsche 928S costs DM 100,000 including German VAT which is a good deal less than we have to pay because this works out at about £29,500 with an exchange rate of 3.4 DM to the pound.

On this basis, conversion to a rag-top is DM 85,000 and for another DM 10,000 you can have a hard-top, which rather defeats the point, but still with German winters being what they are it must be money well spent. Going on the same exchange rate, the b+b conversion works out at £25,000 without tax, which is some 10 grand more than the Lynx version. 

Where the b+b car scores points is the superb interiors they offer for all their cars. The picture of one of Buchmann's interiors illustrates this. Despite being a 911, it serves to show the extent of the work which includes covering with special b + b material for DM 18.000. There is also a sound component stereo system based on the Blaupunkt Berlin for DM 12,800 but again these prices are without tax which must be added.

The address of b +b Auto is Orber Strasse 6, D-6000 Frankfurt am Main 61, West Germany and the telephone number is 41 00 01.