Friend of mine had a Saab and here is a list of his engine Modifications.
Nordic Stage 2 ECU
Taliaferro intake
OEM REMUS free-flow sport exhaust
3.5 BAR Fuel Pressure Regulator
BCPR7ES plugs
These made it fly. Sadly it got written off a few months after he got it
The cars are generally quite heavy so save weight wherever you can - see if you can track down a carbon fibre bonnet.