Tunes are VIN specific and cannot be transferred. What you're looking for is to buy a handheld tuner for either Elevate or Shark. Expect to pay ~$150 for a handheld tuner.
You can then order a tune for you car for ~$450. Still cheaper than buying it new!
Elevate tuners only work with Elevate tunes.
Shark tuners only work with Shark tunes.
I would discourage going with any other company for a tune. The indie tunes have shown very bad outcomes on these cars, Volvos are finicky.
There are some other brand tunes out there, but Elevate and Shark are truly leading the way at this point, and they'll be able to accommodate any mods in your future.
Important to note, the handheld tuners can only store 3 VINs and 5 tunes per VIN. Use this as part of your negotiation on buying a used handheld. Like I said, don't spend more than $150.... Some people will ask for more, but I've sold and bought 2 at that price.
Both Elevate and Shark can erase the tuner if it has already reached it's max capacity for VINs.
Personally, I would suggest owning rather than borrowing. If there's ever a problem, or if the dealer reflashes the ECU, it's nice being able to reload the tune.
Also, some tunes (most Stage 2+, but occasionally a Stage 1) will not pass the readiness test with emissions. So if you have to run annual emissions, it's nice being able to temporarily flash back to stock.
I think the new owner of my S40 is only running the stock tune because his wife doesn't like the extra boost when she drives. I'll have to follow up with him, but he may be willing to sell the handheld.