ST is a nice piece of kit but the quickness can soon be sorted if you get a wolf 285 converted one. there's a few around. there's a red one on pistonheads at the moment. Few mods here and there on the ST and you can easily see 260-270bhp. But its a hell of a lot more money to start with but will probably last you a lot longer than an RS or a cossie and obviously is newer.

Up to you though. And just to add something else lol, why not try a Focus RS? Cheaper than an ST and still an RS