Been thinking of a drive to England to have DMS remap the ECU or possibly a trip to Norway to have ESStuning do the job. However, I think a simple tuningbox will get me 90% of the way and from what I read and hear, the stock 535d is the job already, without the tuning done, so a standard kit may just do it! (I only get the car in 2 weeks and I drive a 2008 E60 520d so I'm bound to feel a little improvement, even with the stock 3-liter engine). I've chip tuned 2 cars previously, one with a box and one with a remap and though you cannot compare directly, I noted some changes in both cars, notably to mileage but also a little on the pickup side so I'm a little undecided what works best; the high dollar custom remap job or the run of the mill cheapobox with zero surgical incisions but I'm willing to give it a shot for my new E61 so if you have a box lying around, collecting dust, give me a shout and let's work out a good price.