Moving back along the drivetrain we come to the rear axle. This was also removed and some fairly innovative thinking applied. The differential itself was removed from the axle and replaced with the 40% locking type limited slip differential from the RS/Series X parts catalogue. Later cars based upon the Injection Special used the standard fit 25% locking unit which had a slightly softer action. It was found at high speeds that the differential would overheat. This is hard to believe as SVE had already tested Injections at 130 mph for hours on end, over 10,000 miles, with no failures. It can only be assumed that Tickford did the same thing at 140 mph and found that the RS limited slip diff would overheat. Whatever, a new and expensive casting was tooled up. The alloy casting replaced the standard differential cover on the axle casing. With cooling fins cast all over it, this part allegedly reduced differential temperatures by 10 degrees C.

The next thing to come under Tickfords scrutiny was the handling, they knew that the key to making the Capri handle was to stop the rear axle moving sideways under hard cornering. They had found that the axle could move by as much as 1.5 inches sideways in a kind of lozenging effect. The solution involved using two forward facing radius arms that pointed outwards from the centre of the axle to the leaf springs, similar to a Group 4 racing MK2 Escort. These arms were fitted with bushes at both ends to avoid bracing the structure in one position for the axle has to move up and down freely. Some of the aftermarket kits that used this principle did not contain bushes and would therefore limit the vertical movement of the axle, using the flexibility of the arms to allow movement rather than bushes.

Initially the cars were developed using the standard drum brakes at the rear with harder linings. Thankfully the production car featured rear disc brakes. These were a development of the versions used by CC Racing on the 3 litre Capri racers. They required the use of a fully floating halfshafts machined from the standard items and a new bearing assembly on the axle tube to accommodate the discs. They certainly worked, although they were prone to stop working so well as they were poorly protected from salt and road grit. The halfshafts were sometimes incorrectly made with a sharp angle in their machining instead of a radius, causing stress fractures and subsequent breakage.

Restyling the car was the job of Simon Saunders, Aston Martins stylist at the time. He was mindful of two influences in the eventual design that was to be fitted to the car. The original meeting had proposed "an 80% Vantage" and it made some sense to try and give some of the big Aston's butch look to its new cousin. Thus he started the restyling mods by blanking off the grille in a similar manner to the old V8 Vantage of the time. This would require another way of cooling the car and it was obvious to try and put a revised cooling duct into a new front spoiler.

This arrangement certainly suited the Capri. It was to require modifications to the front centre of the metal valence to fit and remodelling of the front bonnet to fit the new grille. This alone took five hours of labour, but then cost was never a consideration. A dramatic shaped rear spoiler was also fitted which allegedly cut rear end lift to zero. The front spoiler was claimed to reduce front end lift by around 70%. As a result, the Tickford Capri was an exceptionally stable car in all weather conditions. The prototype car and the first show car were both fitted with a flat moulding under the fuel tank to further aid airflow under the car, this feature was to be dropped on production cars. Considerable wind tunnel development was conducted and the prototype car had a drag factor of 0.36, compared to an Injections 0.39.

From the first styling sketches all Tickford Capris had a moulding between the rear lights, effectively joining them together. This was possibly something of a styling first for the car. Saunders also styled side skirts and a rear bumper moulding that matched the front to finish off the cars look. The bodykit was in many ways the very first of its breed.