Easier to swap in an LS1 (they made a FWD version!). Not even kidding. The 2.8 would use a completely different ECU and wiring harness. Custom motor mounts, bell housing adapters, exhaust fabrication, etc. Would be a nightmare IMO.
SaabCentral forum the most comprehensive Saab resource on the internet. Join our discussions on the Saab 9-3, Saab 9-5, Saab 900, Saab 9000 and all other Saab models, choose your forum.