The s is my dads toy and he is hard of hearing and complains about how the radio doesn't get loud so I'm out to figure out if it is the factory head unit or the factory speakers that suck.

He wants to keep a factory head unit so I was thinking a newer s2000 head unit would be more powerful, is that true? Or should I just replace the factory speakers and keep the 01 head unit?

 

Add an amp and better speakers. A newer head unit will probably have a better built-in amp but the improvement will be minimal. You might want to read up a bit on car audio. Don't overlook existing posts as this isn't an uncommon question.

 

A bit of both. You can keep the factory HU and put in great speakers and still not get great performance. Same thing if you switch HU and leave teh OEM speakers. You will get an improvement if you just upgrade the speakers, but it won't be a large one.

 

The Headunit will be the best bang(value, functionality, loudness, clarity) for the buck.

A forum member here had tested a stock ap2 headunit and speakers. After this test, he tested my ap1 with stock speakers and a kenwood excelon headunit. The difference was not only evident in the test, I can dramatically hear the difference in clarity at higher volume levels.

I was going to modify the speakers first and amplify them. The test results simply suggested otherwise; Subwoofer. The speakers lack in low frequency.

Plus, speakers alone with the stock headunit won't make much of a difference, if any. In fact, in other applications(not s2000), after market speakers mated to a factory headunit yielded worse sound quality.

 

HU is really the problem, the amp in it is a POS. If he wants to keep that, you could probably get away with just adding an amp between the HU and the factory speakers. Obviously your best bet would be to replace both speakers and HU and add an amp, but if he wants to keep the factory HU, then just add the amp, it will do more than replacing the speakers

 

I'll add a little more info:
As the main complaint is volume, you need to add either more power or use
more efficient speakers. The OEM speakers are pretty efficient (though the
'01 speakers do not sound very good), so changing the speakers alone would
probably make the volume problem worse, not better, though the sound quality
would improve.
Your options for more power are:

• swap the headunit for a more powerful one. Different years' OEM headunits
  are not significantly different, so you'd probably want to go aftermarket
• add an amp
• add an additional set of speakers behind the seats/in the headrests (the
  OEM headunit has both front and rear speaker outputs, though only the fronts
  are used)