After various consideration I decided to get Tubi "test pipes" for my '97 550 Maranello in addtion to my tubi exhausts. After the installation the mechanic did a reset and recheck of the ECU. The message showed that the O2 sensors and the thermo couples are defective. When the engine started up the check engine light and slowdown light started blinking on and off!
But the engine and exhaust note sounded so nice!
The mechanic said that there is no danger and that the car will drive normally!
They told me to take it home and I did. The drive was sweet! But the lights bother me a lot. I was wondering if anybody can help me to solve this nagging issue.