well, after consuming the first 17-18 pages of this thread..I gave the spring frequency and next step around shock fluid tuning a go. (just into this hobby 6weeks or so)

B5 rear w 17.5 originally had white rear and green front springs. using slomotion ( benefit of getting into this 3 years after this thread started) on the iPhone i was able to confirm I higher frequency in the front and reset to middle top positions and end up adjusting frequency to match the rear landing on black front springs. beautiful.

it's a reedy 17.5, peak 90c 4000mah battery spectrum servo and futaba or 304 sb receiver ,viper vtx10 black setup.

cheating a little I didn't start w 20 weight oil, and w some of the advances in the b5 setup I left the stock setup 1.6 Pistons in the front and 1.7 Pistons in the rear.
I landed on 32.5 rear, 35 front losi shock oil after two other combinations. ran the track between and felt/looked like the right mix and pack. and car felt more planted and stable to the track than ever.

onto RC and the next steps in the process.. thanks to the contributors so far!