How to use Ipad for best sound

I have all of my music stored on a pc using jriver playing flac files thru a bel canto spidf converter to a havana dac. I really like the way it sounds. I purchased an ipad to use in the car. I have tried various ways to convert my flac files for use on the ipad, acc with boosting the kbps to over 300, using jriver converter to mp3 to the ipad, and using lame to convert mp3's. I have had mixed results with all the methods, but nothing has blown me away or left me satisfied. Am I missing something?
FLAC is a lossless compressed format. You should convert them to Apple Lossless Audio File for best result. If you don't have tools to do that, than convert them to AIFF first and than convert AIFF to Apple Lossless in iTunes.

You can also play AIFF in iPad but it will take up more space than Apple Lossless.
Since you are on a PC, you should try dBpoweramp for your conversions. It will let you do the conversion in one step to just about any format. I store all my masters in FLAC and then convert as required.

You didn't mention how you were coming out of the iPad (headphones, FM transmitter, etc.), that could be much more of a problem than just file format.

Also, as of about 2-3 days ago the new VLC Media Player for iPad is available as a free download. It plays almost all video and audio formats. I haven't tried it on FLAC but I'll bet it works. It's a "must have" for video on the iPad.

Put your music in apple lossless, in your iPad. Get a new Apple TV and use the AirPlay feature (software update in November).
I use my iPad for the same thing, as I travel by car a lot. I have everything in Apple Lossless, and it works great. I even use Pandora streaming while driving cross-country. Nice. I would offer 2 suggestions to increase the audio playback quality, above what has been given already.

1. Get a connector that bypasses the internal amp of the iPad, and simply sends the signal for the amp in your car...which will be much higher quality. This eliminated any distortion issues I had, especially in the treble. Couple bucks on ebay or Amazon, makes a HUGE improvement.

2. I researched the FM radio broadcast connectors, and discovered that the tape-adapter actually offers a larger frequency range than FM radio does. After some research, I settled on the Sony adapter as it had the highest ratings on Amazon.

I have been VERY pleased with this setup. Great audio quality, along with the convenience of the iPad. Anyways, hope this info helps man.

Mot more thing. Most car audio shops now have a kit they can install with the Apple adapter on the end, so you can plug it right into the amp. Might want to check that out as well. Under $200 bucks.

Your best bet for the car would be to get a receiver than has iPod control built in. This way music selection is controlled by the receiver and not by the iPad. Makes things a lot easier. I have an older Alpine with iPod controls. Haven't used a CD since I bought the iPod cable for about $50. That was the first or second generation of iPod control Alpines. The newer ones improved a few things, but its basically the same thing. I highly recommend them. My wife uses a cassette adaptor in her car with her iPod. Far too clunky for me. She doesn't mind it because she only uses it on longer trips, and uses the shuffle feature. If she used it like I do, she'd hate it.

As for home use, there's a camera attachment for the iPad that has USB digital audio output. Connect that to a USB DAC and you're good. Or you can get a Wadia iTransport and a dock extension cable (I've seen them for about $30 or so) to use the iPad. No idea if the iTransport is compatable with the iPad though. I don't own either one. While I'm on that subject, make sure anything you buy is compatable with the iPad. Some things aren't compatable with the iPhone, believe it or not.