It is not just an engine swap. You'd need to swap the whole gearbox, electronics and hybrid system too.
The Toyota HSD gearbox is totally different from the Insights CVT - if you have that on hand, because the 5 speed MT was more popular (and economical).
The Insight is not the largest of cars around, it might not fit.
The Insight has a low carrying capacity, so if you increase the weight you need to upgrade the suspension as well.
If I had a Gen1 Insight I'd like to install a small PHEV booster pack.
I've got a Gen2 Insight and I sure want a small PHEV booster pack in that
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2011 Honda Insight + HID, LEDs, tiny PV panel, extra brake pad return springs, neutral wheel alignment, 44/42 PSI (air), PHEV light (inop), tightened wheel nut.
lifetime FE over 0.2 Gigameter or 0.13 Megamile.
For confirmation go to people just like you.
For education go to people unlike yourself.