it's a good base and it is easy to try and spend a fiver here a fiver there sticking bits on, but it will look pants.
As said, keep the original parts, get it lowered a little, get some 15's - maybe better off with a set of ZS wheels, cost about 150 with good tyres on.
If you find some cheap enough, get a set of front recaro's and fit MK3 subframes to them, will make you will like your doing 100mph stood still.
maybe spray the grills in a matt black.
Have a look at the euro look fiesta's on various sites, clean smooth sublte mods, less is better type of thing.
Forget engine mods, they will make no differnce in performance so not woth the cash.
get onto
www.zsoc.com they have bits come up for sale all the time.