Hi mate and welcome to ukcougar.com. What version of Cat did you get? Big issues would be the wishbones - expensive repair - Timing belt on a Zetec, does it have any service history? If it's a V6 no need to worry about the timing belt as it is a chain and they very rarely cause any problems. Sorry I can't help you with Insurance cos I am an old git who only pays 190 quid for my 2001 V6 Fully Comp Protected.
As for modding, just have a look in the Garage Section, once you have subscribed, and you will be amazed to see what can be done. Hope you have plenty of money as once the modding bug strikes, your wallet will be feeling a bit light constantly.