a lot depends if you're a competant DIYer or if you're going to get it done at a bodyshop. It's all do-able so it depends on you're skills and your budget.
My mk3 has a bit of rust along the top edge of the windscreen that I'm going to remove with a Dremel, treat with rustcure and fill, then paint.
You can get wheel arch kits for most cars and sills aren't too hard to fit.
£200 isn't a lot to risk, and if you do it yorself the bits you need wont cost you a lot. Do it a bit at a time and you could have a nice little motor for not a lot of money
