Audison bit-one/speaker upgrade for those of us with non-ML audio in a 250?

[el_bandido]

I've got a spare Audison BitOne laying around; I'd been contemplating upgrading the audio system in the Lexus for a while. Has anyone used an Audison in a 250 before? Could do with any tips. The prevailing thought at the moment is to add an ML subwoofer and upgrade the component speakers, use the Audison as the processor for it all and see what improvements can be made. I'll be integrating a hands free system to the Audison; it had occurred to me that it might be a good time to buy the android head unit I've been looking at, along with a decent DAC. Is the information on speaker sizes and recommended upgrades available anywhere? I've got the factory premium audio, which is 12 years old now. 

[Linas.P]

There is no such thing as "factory premium" on mk2 IS ( mk3 has standard, premium and ML). It is either 13 Speakers Pioneer system or 14 Speakers ML. As well there is no point upgrading Standard-Sub with ML-Sub. They are both 200mm and I doubt there would be any difference.. if you really want to upgrade sub get something aftermarket.

The main difference in ML system is better quality amplifier and 1 extra speaker, that is about it. Both ML and non-ML systems are very good and I would be amazed if aftermarket system sounds better than standard. I have heard many original and aftermarket systems, but I am yet to see one which is better than standard Lexus 13 speakers set-up, except 14 speakers ML. I guess the only reasonable upgrade is more powerful sub if you much in low frequency tunes, but that is about it. Any other changes will make it sound worse.... it could certainly be louder, but in terms of quality it will be worse.

In terms of speaker sizes:

• 4x25mm tweeters 
• 4x65mm mid-woofers
• 4x160mm mid/low-woofers
• 1x200mm sub-woofer

ML has one extra:

• 1x65mm mid-woofer (center console)

As well ML speaker arrangement is different - Standard system has 3 speakers in each door and sub-woofer on rear window sill/deck vs. ML 3 in front doors, 2 in rear doors, 1 in console and 3 on rear window sill. I personally prefer standard layout - it is overall better, but ML one is more driver/front focused. As well ML rear (which are on windows sill instead of rear doors)160mmx2 are kind of conversions. The speakers themselves comes as 100mm, but they are in 160mm frames.

If I do any upgrade, to my system I would leave all speakers as is and would add like 500w active sub in the boot.. that is it.