Hi. I went to through the same issues a few years ago. I couldn't find an off the shelf kit for the tie bars so made my own using the original anti roll bar. Have a look for Dave Andrews on Google. It's got loads of useful info including some drawings for the brackets. As for the springs, 120 is about right. Size depends what coilovers you have at the moment. If they are the original Zimmerman's it is well worth replacing the whole units. I managed to find some used ones which fitted fine. Lots of people recommend Dave at Dampertec who knows his stuff about these cars. Having done the work it's great to see the wheels moving up and down.