The reason you probably got the wide range of answers is because there are a couple of way to tackle this.
One is to simply swap over the cans and the chip, without touching anything else. It will run fine, bit won't be setup as good as it possibly could.
The other is to swap everything over then fine-tune it by adjusting the fuel/air mixture ratio, resetting the Throttle Position Sensor (TPS) and all sorts of other fiddly stuff to get the fuelling as close to perfect as possible. While this will run really well, it takes a lot longer to do hence the higher cost.
If it was me, I'd swap the cans & chip over myself (no more than two hours to do this) and take it out for a ride. If it runs like a bag of spanner you can then take it to a dealer or place of your choice to get the final tweaks done.
The exhausts can be fiddly, especially if they've not been off in a while, but the careful application of WD40 and a rubber mallet usually works wonders for me