There is one thing i will never do without and thats my wideband, i have mapped mine myself on an e manage blue running 1 bar td04 and going strong, i no what i done to the car i no my air/fuel and i have no det, a wideband and some det cans is a little price to pay to monitor your tune weather it was done by a pro tuner or not, i would imagine the tuner checked the static timing while mapping if he where any good, i would say u ran lean and melted pistons.