Humble, I think it's definitely doable. Out of our 100k (these are rough figures... it's been a while)
Around 20k site costs
Maybe 8k on the kitchen... we didn't have a butler's pantry as standard in the plan so had to create one (Bridgeport 38) and splurged on stone in there, and also redesigned most of the kitchen cabinets adding an appliance tower, overheads, almost all cupboards and extra glass.
10k on tile upgrades
That alone is nearly 40k.... I think you can do it.
My advice is to divide your upgrade list into 3.... must haves, really wants, nice if we can... then if you go over budget and have to start eliminating things, you know which list to start from. I've heard of quite a few people jiggling things on the spur of the moment and then regretting what they delete. If you are really clear about what is and isn't important (or what can be done over handover) it makes eliminating things much easier and less stressful.
Our electrical was under 3 k. But we don't like downlights... that helps keep it down.
In 18 months, there's one light I wish we'd added, and 3 places I wish we had a powerpoint. That's not too bad.