Given your $$$ estimate for the OH which I believe to be on the very high side, you will now pay $87,500 for 0 SMOH on the exact E model you were willing to pay $69,000 for with an unkown engine and 1400 SMOH. If you believe in the TBO numbers, you were in for an OH in the not so distant future anyways.
It seems you have been in the market for a while and you know what you want. If there is something similar or better out there with 0 SMOH and for =< $87,500 you should walk.
On the other hand, there was a recent article in The Aviation Consumer and local shops actually scored pretty well on over hauls. What do you know about the shop that is supposed to do the OH? If it is done to factory specs and has warranty, you might get the plane you want for $75,000 at 0 SMOH versus the $69,000 with an unkown engine and 1400 SMOH. If you squeeze the seller for a couple thousand $$$ more, you are pretty darn close to your original budget.
Looking at it from a different angle, if you found this exact plane on the market with NDH, a well documented recent OH, < 50 SMOH and all the upgrades you want, would you pay the $75,000 or maybe even more?