Calibration Dyno Remote Tuning Motorsport Support Impressions History PNPECU PNPECU Wiki Contact



GSTuning is today synonymous with me, Gunnar Reynisson or Gunni.

GSTuning is not related to any other company in any country also named GSTuning or any variation of that name and definitely doesn´t mean the same as they will mean, GSTuning is short for Gunnar and Stefan Tuning.


In early 2019 I worked with Claridge Customs and Boxers Engineering. We jointly developed and built a hub dyno that GSTuning UK now uses for customer calibration.

In fall 2018 I started working for Aston Martin Lagonda as GSTuning UK as a senior calibration engineer at special projects where I worked on the Aston Martin Valkyrie V12 project.

The early years

Me and Stefán started GSTuning in 1998 at the age of 18 as a side business to begin importing and selling aftermarket parts for car enthusiasts in Iceland. Over the next few years we built some turbo conversions and engine conversions for ourselves and for customers.


In 2007 I moved to Great Britain to study Motorsport Engineering at the University of Derby, when that had been completed I went on to study Race Engine Design at Oxford Brookes University.

I started working for Cosworth Electronics before the end of university providing application support to Pectel ECU customers. I learned alot at Pectel from the great people I worked with.

After University

After moving back to Oxford I started working for Prodrive Motorsports in 2012 where I learned even more than I could ever imagine. During my 6 years at Prodrive I managed to work with some great people and gained a wealth of engineering experience working on some amazing projects.

Among the Prodrive projects I was involved in were the Aston Martin Vantage GT3, Aston Martin Vulcan GT3, Renault Megane RS WRX und die neueste Aston Martin GTE / GT3 2018 Version.

During my time in Iceland, at University, Cosworth, Prodrive and Aston Martin Lagonda I have always kept GSTuning busy by providing ECU calibration support to car enthusiast in the aftermarket. Despite having a full time job all those years I have been involved in over 200 projects world wide.


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