Okay my dad is currently trying to purchase a new battery for his '98 740il. The dealer wants $300 because it's specially made with vents to mount in the trunk. Anyone know of some other brands that he could purchase for the car and not pay the stealer $300? Thanks a lot.

To get a Duralast that fits the E38, look up www.AutoZone.com for a location near you.

To get a Douglas (OEM) that fits the E38, look up www.BatteriesPlus.com for a locaiton near you.

Both are in the $90-120 price range and work fine.

Interstates are good. About 110 or so.

Okay my dad is currently trying to purchase a new battery for his '98 740il. The dealer wants $300 because it's specially made with vents to mount in the trunk. Anyone know of some other brands that he could purchase for the car and not pay the stealer $300? Thanks a lot.
...like others have stated...the Duralast 49D, Interstate MPT-93, and Douglas 95R batteries can be had for much, much less ($79 for the Duralast) and they all come with a free vent kit (make sure the kit is attached which ever brand you choose to buy) to hook up to the vent hose in your Dad's car.

The battery is also VERY easy to replace yourself...so don't pay someone to do it...if they'll do it for free...that's a horse of another color! :D

Here's a link that has just about all the info you need for making a choice and how to hook up the vent hose and secure the battery in its location: http://www.bimmerboard.com/forums/posts/33924/

As far as the dealer scaring your dad into thinking the vent hose is something special...here's a pic of the vent hose attached to the orig BMW battery...the hose is located at the rear of the battery compartment and vents out the to the side. Just remove the little black L-shaped adapter when pulling the battery out. You attach your new battery to this hose...that's all...and they want $300 to do this plus the cost of the battery. This can be done in 15-30 minutes and that includes opening the trunk and unscrewing the 2 battery cables etc.:
http://memimage.cardomain.net/member_images/1/web/433000-433999/433594_225_full.jpg