I have subs running through my stock head unit, is it worth it to upgrade to an aftermarket head unit?

I recently got subs in my '07 fj crusier. Instead of purchasing an aftermarket head unit, I bought a converter so I didn't have to drop an extra 100 bucks. The guys at the audio place that installed it said that my subs would sound much better and hit a lot harder with the aftermarket head unit, but I wasn't sure if they were just trying to get more money out of me or not. I'm on a budget because I'm a teenager and only work on the weekends. Is it really worth it to upgrade? And if so, do you have any recommendations? I have 2 diamond d1's running on a sony xplode 1200w amp, in a custom ported box.I have subs running through my stock head unit, is it worth it to upgrade to an aftermarket head unit?
I've installed hundreds of subwoofer/amplifier systems, with factory head units and with after-market. In terms of sound quality, you wouldn't be able to tell the difference between the two types of installations. If your factory radio has all the features you want, there's no reason to upgrade.