Yes, there's a forum member who makes the extra wires needed to add passive entry.
IMO, it takes about the same time, the savings is in $$
You still need to run the harness, make the connection to the door connector, etc. and replace the handle. Time won't be much different.
But with his small harness with just the passive entry wiring, you save $$ not having to buy the whole thing - especially since for a long time they were back ordered and hard to come by! I think that's what prompted the making of the passive entry only harness.