You can never have too good brakes, but as you arte just stixking wityh looks, a decent set of discs and pads with maybe a better quality fluid will work wonders. I see quite a few people use ferodo ds2500 pads, never used them myself so can't say for sure, but I think they are a good "fast road" pad. As for other stuff, the ususal smoothing and de cluttering looks good, and you can pull the light unit apart and tint the headlight in black (or any other colour really), its easy to do, just pull the light unit out, strip the bulb etc all out, put it in the oven on a low heat to soften the glue so you can pull the unit apart, paint it and do it all again to re assemble. That fiesta you pictured has had it done. Aloys also look good on the mk4, ig you are on a budget, escort GTI or RS2000 MK6 alloys look good (but it won't be the most original mod).