Battery OPTIMA or OEM Subaru

Ah, but the Red Top fits in the TDI without problems. About $109 at Costco.

I have the stock VW battery under the hood and an optima yellow top in the trunk with a 5 farad cap as well, now Im doing DB drags, and I also use my car as a daily driver, I have yet to see a single bit of strain on my electrical system and belive me I have two Autometer volt guages just to be safe for monitoring.

Ran a dual battery setup in my S4... was easy. Ran a PAC relay from the main battery to the rear setup with a battery isolater. Battery charged when the stereo was on, and stereo was only powered by the Optima yellow top in the trunk.

I've had an Optima ever since and never a problem...

I have a blue top (couldn't find yellow locally) and I love it. Damn battery box doesn't though (had to chop it up and piece it back together to make the battery fit).

Optima batteries are some of the best batteries you can buy. THey are gel cell batteries, not like a conventional dry cell like in your car now. They are also deep cycle batteries, sealed so they never leak, and have 2 sets of battery terminals. They are practically indestructible.

The VW battery tray in the 91 GTI is trying to eat my Optima The little bracket that stays in the car that normally holds the bottom lip of the battery is cutting through the case of the Optima because of the 6-pack design of the case. I had to use a small section of wood to put between them to keep it from cutting it any worse. The tie down bracket that can be removed from the car doesn't fit the Optima very well either, again because of the the 6 pack case shape. I had to use a grinder wheel to grind a section out of the bracket so it would fit around the cylinder shape of the case.

I ran a red top optima and it died in 8 months, now I have a yellow top and I am not impressed at all.

I have had nothing but problems with optimas and I am far from the only one. Go with either an Odyssey or a walmart brand yellow top. I had one sitting around for 6 months hooked up to a non running vehicle. Tossed it into my gf's bronco to fire it up one day and it started right up. Also, I run those in my diesel, and I left the interior light and cargo light for over 12 hrs. Got in and she fired right up.

FYI New optimas are the suck. Good luck though.