looks good but as said you'll need to sort an exhaust which will set you back somewhere in the region of 250-350. check out powerflow, exhausts uk, or just look on yell.com for exhaust places near you, there might be a small independant exhaust place thay will do you a stainless backbox for next to nothing. you will probs find most will charge alot as there is only a very small gap to get two pipes through and a tight bend is required, unless you would be happy to just get a single exhaust and a dummy at the other side, would work out alot cheaper, or get them to just bend one pipe round and just join a second pipe to it.
lower it shouldnt cost you more than 100 for a set of spax springs and i would of thought most garages would do it for around £50 fitting. The backs are easy enough to do yourself as you dont need spring compressors. just a decent trolly jack, a spanner and job done.
a set of 18"s can be picked up for cheap. £400 for a new set of 18" with sh!t tyres like.
https://www.alloywheels.com/search.asp?s ... strSize=18"&strSort=Low&numRecordPosition=1&strSearchCriteria=any&PT_ID=all&Make=Renault&Model=Megane%2003>
Then you'd need to get a front bumper sorted, i think only way to go with that rear would be a 225 front end or something like this would look pretty cool.
https://translate.google.com/translate?u ... uage_tools.
Painting the front and back bumper and the side strips you should be looking at between £250-400.