I (95 kgs) sail a formula 159 with a Tushingham Lightning 10.3 twincam freerace sail (compareable to V8), a 520 carbon 75 mast and a Nautix Jumbo formula aluminium boom.
I do press my equipment very hard and to me this set up works just fine for recreational blasting. You will NOT win a race with this kind of equipment but it's seriousely okay for planing, blasting and up and down sailing on a formula and in lighter winds you can kick ass on some smaller freeriders. And the price is rediculous compared to real formula equipment. It has to be said that the differences will start to appear in stronger winds where a 100% formula rig works just better (takes a whole lot of wind and stays controlled). Anyway I can comfortably sail my freerace rig up to about 20 knots and after this I can easily (and prefer to) go on something way smaller.
Should I choose to upgrade something I would get a carbon boom as the "feel" of a rig very much depends on the stiffness of the boom.