Nearly 12 months on and absolutely no issues.
The type of dollars I paid were Australian Dollars.

Price will vary on what you want and how much work needs to be done. For example, my car does not have SI Drive, so only one map needed to be tuned. SI Drive requires more maps to be tuned.
My tune cost me $600, but there are other costs to consider on top of that - the cost of petrol consumed during tuning, the cost of a Tactrix OpenPort 2.0 cable to allow you to connect your laptop to the car, etc.
Tuning continues until both parties are happy and any future updates to that tune, eg: for new physcial engine modifications, are only about $75 each re-tune (not per mod).
Obviously prices are subject to change. Post a query to west_minist (Edward) and he'll be happy to provide you answers to questions about his business. He's a friendly bloke.
I was going to procrastinate, but I put it off...