Re smoke - white is unburned fuel, common on cold diesels, blue is oil, can settle in the engine ovenight if the valve seals are worn, but not a huge problem, just watch the oil consumption. White can be steam, but if it is then the engine will usually be down on power quite a lot.
Re bull bars, yes be very careful as you are in Scicily and EU type approval regs apply, UK opted out. Is it on a UK or Italian reg? If its Italian a non type approved mod can be an MOT fail (at best) or impounded at the road side and on the spot fine (aka contribution to the Police party fund, don't expect a receipt!). I don't know how strict they are in Italy, but in Germany its a huge issue, they have been stopping UK registered Mercs for having after-market wheels that are UK legal but not EU approved. Mercedes are focing owners to buy approved wheels that, guess what, cost 5 times as much and are only available from MB.