I have been undertaking remapping and DPF deletion for a number of years. The only basic important pieces of advice I can provide are: use a reputable company with tried and tested files, use the correct genuine equipment and undertake the correct safety procedures. The people I use offer full training and full telephone support and advice.
I have been to customers who have had poor experience with "cowboys" offering cheap prices which are only possible with cheap files and equipment.
I have been in the trade for 25yrs now and find remapping most rewarding both for financial and personal reasons. Tuning in the old days generally meant improving the performance of a vehicle because it had got "out of tune" and rectification brought a smile to a customers face. This does not happen nowadays and generally poor performance meant a component failure and lots of money to put it right. Remapping is taking a perfectly good car and transforming it into something better and the smile on a customers face as I said earlier is most rewarding. DPF deletion saves the customer a lot of money.....which also brings a smile to his face.
In summary, I have found it easy, a good money earner and brings me much job satisfaction.
Regards
Pete M