yep, definitely insist on the 4-point. you'll need that with the Tahoe.
i have a similar sized 23SS and i wouldn't use the E2 with my longer Avalanche. i have the 1000/10000 4 point Equalizer and absolutely love it.
the dealer is just trying to cheapen the deal and BS you about too much WDH. the E2 is made in China and is much cheaper for him to buy, while the 4-point is heavier duty and made in the U.S., plus it'll help more with the shorter wheelbase Tahoe.
and Zoe the Wonder Dog(R.I.P.)
'07 Roo 23SS pushing an '07 Chevy Avalanche
Equalizer WDH and Prodigy BC