K&N Air Filter

So one of the best pressies i got for my birthday was an MCAS voucher
Looking through their webpage i saw a K&N air filter for my bike, so questions are, should i bother? is it worth it?
http://www.mcas.com.au/_product.php?sec ... rodid=9634
My last bike had one fitted when i bought it, and when i bought my tracky (which was the same) it didnt, and i really didnt notice any measurable difference.
Apart from adding another bullet point to my specs come time to sell the bike, will it add any value? Should i bother with this or just find some other noticeable bling?
http://www.mcas.com.au/_product.php?sec ... rodid=8672

http://www.mcas.com.au/_product.php?sec ... rodid=9634
My last bike had one fitted when i bought it, and when i bought my tracky (which was the same) it didnt, and i really didnt notice any measurable difference.
Apart from adding another bullet point to my specs come time to sell the bike, will it add any value? Should i bother with this or just find some other noticeable bling?
http://www.mcas.com.au/_product.php?sec ... rodid=8672