Power steering fluid
"I went from a '79 Rabbit sedan, manual steering, to a '93 Cabriolet with power assist. There really is not an appreciable difference in effort between the two.
The big difference is the ratio of the two steering racks, the manual rack took 3¾ turns lock to lock, the power assisted rack, only 3 1/3.
The power rack is much quicker, without the assist, steering effort would be objectionably greater.
I really like the power steering, but having driven many miles with both, I would be reluctant to ever convert one to the other. Root canals are more fun, at least you get a day or two off work.
If you are determined, you'll need a pump, belt and all mounting brackets, a fluid reservoir, feed, pressure and return lines and a rack with mounts."
The Cabriolets are heavier than their hardtop counterparts and, therefore, require a slightly stiffer spring. You can use hardtop suspension on your Cabriolet, however, the ride may not be as good as it should be and could possibly do harm to other related components. When looking for suspension, particularly when upgrading from stock, be sure the springs and/or shocks are made for use on Cabriolets (visit manufacturers' web sites).
Installing Mk2/A2 Golf suspension is not recommended; if it is installed, the ride height will actually be raised. The suspension for the A2 Golf platform is a bit different (hub, length, spring rate) and is really unsuitable for your A1 Cabriolet.
Upgrading the Suspension
This is a matter of personal preference: What is firm to one is too soft to another; what is low enough for one is not low enough for another. However, the table below is a culmination of brands and opinions in the Cabriolet world. Shop around; many companies offer package deals on springs and shocks. Do not use lowering springs with stock shocks and always replace them in pairs (fronts; rears)! It also advised to replace the front strut mounts and bearings at the same time. Some front shocks have built-