Hi mate, if you want a significant performance with your car you have to take a used sc as many have already adviced you. Else if you want some simple mods, you could change your intake air filter with an aftermarket such as K&N. I would not suggest to fit a cat back exhaust since you will not see significant power upgrade and will have to pay for around 400 to 500 pounds. Get a set of lower springs and maybe a set of arbs. You will enjoy your ride more and you will have a significant change in the noise after 4000rpm with the filter. Also change your pads with mintex or ebc and you will also have a better braking. If you manage to save another grand and you do not find a supercharger since they are very rear and get hold of very fast, you can try the light turbo option. They are a few members that have already taken this route and they do not have problems with the reliability and are happy with the performance.