Hi I'm new here and interested in a tune for my 01 540i auto. I'm leaning towards a tune from RKTuning that was a recommendation through his site. Is there any feedback on them...so far they seem good and fair. I'm also not looking to be running around with timing at its max just for results. I want a clean hp and torque improvement without loosing drivability and more importantly reliability. I currently have a cat back exhaust and most likely will drop in a K&N box filter. Along with the minor gains I also know the limiter will be increased. So my questions are, are they any good, will it be reliable and can I return to stock settings if wanted. Thanks in advance.