I know that AFR is fine now. My plan to add the 74mm TB may get that to the edge, especially if I do any exhaust work. I just had Eurocharged Performance do a DYNO Tune a couple of weeks ago. I was getting 195RWH and have added K&N filters since. May have to figure a new air box later as well. Just trying to find bargins while they are available at a really good price. The best time to purchase any item is when you don't need it, always get a better price and it gives you an excuse to do the project because you have the parts. I have SRT6 front rotors and calipers, new SS brake lines, and new ceramic pads front and back to add at some point. Bought all of them a couple of months ago. Just like doing stuff to the XF that make it a better car and more fun to drive.