I dont know your reason, but this seems to be pretty much the most expensive, headache inducing idea. Almost no motor swaps are just simple drop in ordeals, this would take alot of time, and much more money than that initial investment (i'd wager an extra couple grand from that initial investment). At the end of the day, for all your work, you'd end up with a frankenstined V6 with no resale value.
Other than that, some things off the top of my head would be difficulty in integrating the motor to the dash, K member, transmission tunnel differs in size (can be corrected with a hammer if memory serves), I believe the shifter sits further back with the 6 speed, custom driveshaft, placement of all the wires, full exhaust needed, fuel system...etc
If you're dead set on doing an engine swap in that exact car, I'd look for a less expensive option
I'm assuming that you're just a regular person who works on their own vehicle, and this would be work for someone with alot more experience in the field.
If you decide to do it, I wish you the best of luck