I did the same retrofit, but I was not able to find the rivet gun! (checked EVERY store in town, and I was impatient to order it on line)

My friend (who owns a body shop) charged me 80USD to install. The other friend (who owns a BMW dealership), charged me 130USD for the fender flares (that's how we call them in the US!). Altogether,...$210.-!! Not bad, and it makes the car looking better.

Now I'm waiting for the running boards to arrive ($230), and I'll have the body shop install those as well (another $80.-)
Total mod, $520.- and the whole new look! Under a grand, including the oval tips (still waiting!).

I decided to keep the stock 18" wheels (for a while anyway), because I drive on the gravel for about a mile to my house. I brought the wheels "out" to match the flares (with H&R spacers). Cost $600.-

That's how you mod a 3,0 on the budget!