I would say a Scan Tool is a vital tool to have!!
I agree, but I prefer an Xcal2, personally.
That said, you can't really work on these cars without an obdII reader; you'd be guessing, or paying someone else to fix it for you. (Who will use a code scanner to see what's wrong, lol.)
My Boss bought a Scantool that hooks to his phone by bluetooth, and will show you whatever you want; if I ever get a smartphone, I'll buy that asap.
I like being able to take a drive and make a datalog of everything important, then sit somewhere and eat something and see what's going on.
When tuning, I make changes, and drive somewhere else.
Red '96 Cougar XR-7 240k mi. '02 4R70W, PST DS : '03 PI engine, 04 maf, 24lb injectors, 2.5" exhaust, '02 4r70w + Jmod, DirtyD0g TC + cooler + 3/8" lines, 255 walbro fp. Alpine system.
Black '96 Cougar XR-7 (Lazarus) 210k mi PI Intake, '02 4R70W, Jmod, PST DS, GrogTune, Konis, Mark LCA+Poly, racecougar Custom Engine Chain, and JL and racecougar Bracing.
Black '97 Tbird Limited Edition, '02 4R70W, 255 walbro, PST DS, PBR Brakes&SS lines, Toicko Blues & Springs, GrogTune.
I'm not Human enough to be human; but I'm trying to fit in, and I'm learning to fake it.
"Never said Hibbity..." - Brian Williams