What is the minimum SCFM necessary to drive air tools?

SEARS has an air compressor (30-gal. 6hp, vertical) kit (1/2" impact; air-hose; 3/8" ratchet; air hammer) that runs on 120-VAC, and it's rated as follows:
SCFM Delivery At 40 psi 8.6 SCFM
SCFM Delivery At 90 psi 6.4 SCFM

If this is good deal for $299, and more importantly, will it work for the weekend mechanic?

:-) neil
1988 360TE AMG
1993 500E