not sure if its normal but it does look low to me. I had a borla on my lowered G35 and dented it badly when I drove a shredded tire. Borla did replace for free under 1,000,000 mile warranty. Im sure the Borla owners will chime in. we need another member to match this photo so we can compare directly
2010 LEXUS ISF FEATURES:
Readers Rides of the month Modified Magazine December 2009
Readers Rides Super Street Magazine June 2010 2003 INFINITI G35 Rearders Rides Super Street Magazine 7/05
2007 Lexus GS350 / 2007 Lexus LS460 / 2010 Lexus ISF
You have to make sure that the pipes from the mufflers align with the diffuser tips. After I installed mine I realized that the pipes from the left muffler were pointing slightly up (the back of the muffler hanged low and so did the pipe). I just unscrewed the bolt/clamp, pushed that pipe up and tighten the bolt/clamp again. After that, everything aligned perfectly and the pipe didn't hang that low.
You can even see it in your picture how the back of the left muffler is hanging lower than the right one.