Hit the nail on the head AT.
 Guess ill start looking into custom machines.

When shopping around, do yourself a favor and ask (especially when it comes to money), how fast would you make profits to pay for it. Is it for occasional use (i.e. weekly vs. day and night), and are you going to lose contracts because it's not good enough? I get irritated when I read forums where people gloat that they bought a Lynx Aurora A/D and claim it's leaps and bounds beyond a MOTU at half the cost. I believe I can hear a difference between my MOTU pre-mod and post-mod. It's not significant, but that's relative, considering the differences I've gained from better pre's, mics, and musicians. Even my plugins have made more significant differences. 

If you can save to get a good A/D-D/A converter, but getting the best will break the bank, then does it really make sense to get the best? 

"Build (buy) it and they will come" rarely works in the studio industry, unfortunately. A studio with the absolute best converters remains unknown compared to a studio that has made hit after hit, and has the exposure, engineering, and skills to make hits. I made full use of that theology and saved $1,000 buy getting a middle of the road converter for my studio. If I start getting better business, I'll upgrade. Until then, I've got a great converter that works for me.

I think the clock can matter. I used a M-Audio Fast Track Ultra for 5 or 6 years and in November 2012 upgraded to an RME Fireface UCX. I still use the Fast Track when I want 2 tracks more than the 8 the Fireface can capture. There is no doubt that I hear improvement in the sound. The clock helps on the way in and the way out (A/D and then the other way for the monitoring D/A). And I can say that the Fastrack sounds better when slaved to the UCX. I can also say that 24 bit 44.1 sounds amazing to me. But I'm 43 and my hearing isn't what it once was.

The clock makes the biggest difference when recording many tracks at once, and with accuracy in transients. That's where my BLA clock makes a difference.

Ok something I forgot to ask earlier is does everything have to be set to the same rate/depth? My interface, sonar, and my plugins all have the option to adjust these settings in their control panel, do they all have to be set to the same settings?

They should pick up from the master - which would be the interface.  But it is always good to check SONAR's many pages of sync options just to make sure.

I see. I ask be because what if different devices support different rates. For example if the "master" only supports 44k and your soft synths can do 96 or 192, what happens in a scenario like that?

Plugins (including soft synths) rely on the host settings to communicate with the host. What they do internally depends on the plugin.

With the higher priced a/d d/a systems you are paying for stable clocking and well designed low pass filters. If you can hear the difference then it may be worth it to you but as everyone else has pointed out there are many other things to consider.

But would one need one of those higher priced ad da systems if they already had an upscale computer? Or vice versa? Cant a good custom computer handle clocking issues? I lack in both those departments right now and I can afford to get one or the other. So at this point im wondering just out of curiostiy, if I get a good custom pc now, will I still need to get converters later?