The flex pipe installs between the outlet of the 3-bolt y-pipe and the inlet of the 3-bolt cat, and yes, it is 100% necessary.
2000 SVT Turbo 295hp/269ftlb@12psi
#1 for Bendix Brakes Kits!
Knuckles rebuilt w/new bearings $55
AUSSIE ENDLINKS $70
Gutted pre-cats $80/set
A lack of planning on your part does not constitute an emergency on mine!