Design features of the GMD/Milsport struts The coilover struts are manufactured in Japan for Verus Suspension Solutions, to a spec by GMD’s engineers .They are gas-pressuried (to reduce cavitation of the oil damping medium) and the damping is adjusted by means of an anodised aluminium knob situated at the lower end of the unit. This alters the rebound damping but also changes the bump damping to a lesser extent.

The body itself is threaded along its entire length for adjustment not only of the spring length but also to change independently the total height of the strut. This is an important point because the spring mounting collars can be set correctly so that the springs seat snugly without the need for 'helper' springs or excessive preload, then the height of the car can be adjusted independently at its threaded lower mounting. A PTFE coating to the threaded body provides protection from corrosion and allows easier adjustment. The body and damper rod are sealed from the elements using a plastic cover boot. This extends the life of the seals and prevents dust from collecting around the seal area which can cause 'stiction' in the operation of the damper, which has a detrimental effect on small bump absorption and ride quality.

The top mounting of the strut features an anodised aluminium-alloy mounting plate incorporating slots to allow camber adjustment as well as a small amount of castor change. The ability to alter these settings is crucial to optimising the car's handling performance. As for the damping characteristics, this has been designed to minimise initial cornering roll on turn-in (at this point the anti-roll bars have little effect) and this also means that the spring rates can be reduced, which is good news for both ride comfort and grip. The springs themselves are cold-wound spring steel in the universal motorsport size of 2.5in diameter. GMD's engineers have strong views on all aspects of suspension design and is critical of the tendency to use ultra-stiff springing on road cars, which he argues is ineffective on anything but very smooth tarmac. we are no fans of ultra-low suspension either, as this reduces damper travel and adversely affects the geometry. On our own demo vehicle (a 1997 STi TYPE RA Impreza) the car is lowered by a moderate amount, just 15mm at the front and 12mm rear compared with the standard Type RA suspension.

The primary benefit of these replacement strut units is to utilise spring and damper rates tuned to cope with high-speed track driving while retaining sufficient suppleness for road use. It's made possible by the provision of adjustable damping and carefully selected damper valving. A great deal of thought has gone into the design and specification of these new coilovers so you can expect only the best product, designed specifically for your car and your needs. For a full report on the Milsport/GMD coilover suspension see the article in Japanese Performance magazine, issue No91 August 2008