On Modified Porsche Valuations

While my client work includes valuations for many standard Porsches, a high percentage of the original, unmodified cars I value sit outside the norm: perhaps they are low mileage/high mileage, left-hand drive instead of RHD or they may be restorations where the owner wants a higher percentage of the cost to replace taken into account compared to the one-size-fits-all valuation that a club or insurer might suggest.

Standard cars with minor deviations from average, run-of-the-mill examples are fairly straightforward to value. It is all about taking a view on the impact to the retail price of whatever change applies, putting that view into pound notes and deciding where the final calculation sits in the context of the market. Modified Porsches require a similar process, albeit the work takes place over several stages.

My earliest bespoke Porsche valuations were all for modified Porsches. At the time I was working for Glass’s Guide and had just bought my first 911. As an enthusiast of modified cars of all marques and the owner of several examples, I was spending a lot of time attending track days and modified Porsche meets, such as the monthly Ace Cafe German car night and annual Oulton Park RS day. This allowed me to meet and speak with owners of modified cars and understand just how exposed they were to serious financial loss in a write-off scenario.

Back then, Porsches were changing hands for much lower prices. I had a 964RS in my garage for six months; value was somewhere in the mid 30s. My modified 1976 Carrera 3.0 (which I still own today) cost me less than £20k and the higher mileage SCs that people were basing hot rods on were selling for less than £10k. A modified car based on the same SC with restored or upgraded bodywork, drivetrain and interior might have cost circa £30k to build, but, with no real data to go on, insurance companies were forced to look at selling prices for standard cars to settle total loss claims (all claims at the time verged on total loss, as the cars had such a low value).

My first valuation for a modified Porsche was over fifteen years ago, with a Ruf 911 Carrera RCT Evo. Based on a 964 Turbo-look Celebration/Jubilee model, this was a turbocharged car making 425 bhp and incredible to drive. The value was agreed with AON Private Clients in the mid-30s: the equivalent of a decent 964RS at the time. A few weeks later, the car went on a track day and was crashed. The repair estimate came back at well over £50k and so the car was declared a write off. To their credit, AON paid out the agreed value within days. The loss of such a great car was a sad event, but the owner emerged unscathed and everyone ultimately went away happy.

Valuing the Ruf RCT was not too challenging. We had recent market data and the car was well under six figures in any case. Nowadays, things are not so straightforward. Some cars can top seven-figure valuations. A number of my customers run modern GT3s with a list of modifications that can sometimes rival the car’s purchase price. I have hundreds of modified air-cooled cars on my books, from 356s right through pre-’73 911s and up to 964 and 993 retro builds. I also value cars with incredible history: calculating what a famous previous owner or unique race history may add to the value can be an interesting exercise.

While it doesn’t happen that often, I sometimes get valuation enquiries from owners who want to value their car based on a total receipted cost to build. In such cases, I will usually decline the opportunity to provide a valuation, as the desired or target number is simply too high. No market data exists for their aspirations and defending that statement in court in a total loss situation would be difficult. If your current valuation is based on that approach, just bear the overall market data picture in mind.

I work along the lines that there are three end users for every valuation I provide: the owner, the insurer and my own reputation. The client and the insurer are equally important: fairness will always be key to an amicable settlement. Even on modified cars where no similar examples have recently come to market, one must have some form of market data to support the valuation. If an insurer queries a valuation in the event of a claim, I want to be in a position to answer that query with links to data on identical or comparable cars.

All valuations for modified cars begin with a look at the base vehicle: what is under the skin of this machine.?Then we get into the list of modifications and the quality involved. ‘Who did the work?’ beats ‘what did it cost?’ As I work around these cars most days of the week, I have seen lots of examples of work by various specialists and they are not all the same. Modifications carried out by a technically proficient owner may have cost less than specialist prices but the work can be of a much higher quality. The quality of the build has a significant impact on any insurance valuation for a modified Porsche.

As so many owners admire the standard appearance of factory bodywork, modifications are often limited to purely drivetrain and chassis mods. Engine rebuilds are popular and they certainly do add value, whereas aftermarket wheels and track day tyres have much less of an impact. Changes to the interior such as a full retrim to rebuild the seats and delete tired body-colour piping can make a sizeable difference, but smaller, reversible changes such as the fitment of a Porsche Classic radio may only make a noticeable effect as part of a wider theme.

Porsche Resto-Mod Valuations

The appetite for modified Porsches has led to several specialist workshops emerging for resto-mod builds on air-cooled 911s, including SC, 3.2 Carrera, 964 and 993. These workshops build cars to a unique specification for private owners but not all owners hold on to their cars. Even when sold close to the date of completion, the selling price for a distinctive build can sometimes be well below what the car first cost to put together, so it is important to bear this in mind when valuing for insurance.

Owners who keep their resto-mod builds for a number of years might interpret this as putting them at a disadvantage, but every case is valued on its own merits. The beauty of escaping the one-size-fits-all mass market valuation methodology and switching to a more tailored approach is that what you end up with fits you and you alone.

My aim is to provide a valuation where your unique situation is covered to the very best advantage and where the insurer understands that time and effort has gone into achieving the right valuation. In claims for theft or total loss, this start point leads to hassle free settlements. That result is well worth the modest investment in a bespoke valuation.


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