You're bumping after less than 24 hours? You kids today need to back off the Red Bull
In the context of, "how much better than stock are the SWS-8?", the answer is tons. Hands down, a pair of SWS-8 and an amplifier will give you much better results than the HiFi 8" on the HiFi amp.
In the context of, "what the the shortcomings of the SWS-8?", the answer is longer.
It is the best fitting speaker for that location, it is durable, and it is loud. It has a bit of a one-note peak to its output, which quite honestly most people considering a trunk sub don't mind at all.
If you're upgrading the entire system and have more of an SQ sound quality orientation, the sound of the SWS-8 UNEQUALIZED might be lacking. Ditto if you are adding a trunk sub and are looking for underseat midbass woofers rather than subwoofers - SWS-8 do NOT excel at mid-bass.
We do three different levels of underseat upgrade:
- SWS-8 and an amp
- SWS-8 and new front mids and tweeters, and a 4-channel amp
- SWS-8 and new front mids and tweeters, and a DSP 4-channel amp. This helps tame the one-note boomy quality that some people want to tone down. Some people love it.
Now that the MS-8 is in the mix, we are changing that and adding "Ms-8 front and rear, and an amp on the SWS-8". But anyway, you will not be disappointed with the SWS-8 unless you are looking for a high-performance sound system and you don't carefully EQ the SWS-8 in the process.
That's what the JBL MS-8 does - optimize each speaker - so a system with an MS-8 and the SWS8 underseat can benefit from the output and robustness of the SWS8 and the sound quality of the MS-8 DSP.