I have had great success with the advice that I've found dotted around from sports racer. A front lower brace, coilovers and a rear sway bar are invaluable for the mk1.
Mine currently has a 23mm Mitsubishi pajero front sway bar hung in the rear beam which gives the mk1 fantastic rotation under trail braking.
Camber front strut tops can alleviate some of the suspension geometry issues that are encountered when lowering a McPherson strut car. The reduced angle between the control arm and the line formed between the ball joint and the strut top, means that camber is increased as the suspension is compressed (eg during body roll) allowing for better tyre contact during hard cornering. A better method however is using ball joint extenders, but I would never use on ANY car, and would warn others to do the same.
Interestingly, raised strut tops would actually result in worse handling characteristics in two ways. Firstly, they would make camber tops less effective due to the reduction in camber angle changes, especially under suspension loading. A car with factory height strut tops will benefit far more from camber plates. Secondly, by raising the strut top, the new suspension geometry actually results in a LOWER roll center, resulting in higher body roll forces (moments) during cornering.
15 inch wheels with good rubber will be the best upgrade possible. Aim for 7j, with a 195 tyre width and you'll be laughing. 15s will also allow for 280mm brake upgrades, which is something I would definitely recommend as well. Rear brakes are not as important as they do next to nothing. I'm still running 200mm mk3 drums and don't plan on upgrading any time soon.
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