K & N and engine warranty
 

Just bought an 09 Se, was wanting to put on K&N but am wondering if that would void engine warranty?

A K&N what? If you are just installing a filter, no, it will not void the warranty. If you are putting on a whole intake (CAI or SRI), it will only void the warranty of the parts you replace (the air box and tube). However, if the CAI causes engine damage (like if you drive through a deep puddle and cause hydrolock), yes, it will void the warranty.

If you are just replacing the filter, No, it will not void the warranty due to Congress enacting the Moss-Magnusen act some years ago. One warning about the K&N, (and other oiled filters), do not over oil the filter when cleaning it.... the excess oil can & will be drawn throughout the intake tract, and that can be bad for MAF's and the like.