No, it does not have fast track lanes going in or out of Singapore for Business Class. But it's not necessary either. Changi Arport Immigration is very efficient in all terminals. They always have many imigration counters open and the computer systems & immigration officers are very quick. I have been going in and out of Singapore regularly since 1987 and never had to wait more then 5 to 10 minutes maximum. One of the reasons they have been voted "Best Airport in the World" so many times.

Should you fly First Class or Suites out of Singapore on Singapore Airlines, then you can use the seperate First Class check-in area at Terminal 3. That area does have seperate immigration counters for passengers leaving in Singapore Airlines First Class & Suites. This area can also be used by Singapore Airlines Solitaire PPS Club members, regardless of which cabin class they travel in.