both the maxima and the "i" line infiniti are the same car with the "i" being more luxourious of the two. If you are reffering to a "lower control arm" you can either do one of two things.
1. possibly take it to your local infiniti dealership and see if the re-call has been performed already
http://www.dealerrater.com/recalls/Infiniti/I35/
2. you can buy one from
http://www.rockauto.com which range from $50-$90 or buy from Courtesyparts.com listed under Maxima for $145.72 per side "infiniti and nissan list the same part #54501 Left & #54500 Right for both cars"