This isn't critical in any way, I am just curious - and anyway I don't have a 126, just a kit car, so the answers don't affect me at all, but does changing the front suspension actually make much difference to the car?
The 126 is pretty light, so I imagine *any* suspension will be fairly stiff or hard in that there isn't a great deal of weight there to compress any spring of whatever type. Does changing away from the leaf spring change the steering handling at all? Of course there's the issue of adjustability, and I imagine making the spring softer might give a smoother ride, as I guess the leaf spring will stiffen with age and with corrosion between the leaves...
Also, of course, I guess you'd make this change along with others like maybe different wheels/tyres, and as here discs too which must change the sprung weight and suspension... lots of factors at play. Is it like tuning the engine, no point in doing just one change, you really need a whole 'set' of changes to see the benefits?
So, having shelled out for the new kit, what is it you get for your money? [and I recognise that in any event there's also just the pure fun of customising your car

]