Honestly, I find the mid & high fine in my old 500, & even the original head unit has a decent sound, its the lack of bass from the original speakers that lets it down! I was going to upgrade the door speakers, but rather than fitting 6 & 1/2`s directly to the door frame, I was going to "hollow out" the original speakers & use the outer ring to mount 5 & 3/4`s, but I was going to box in the back to give it an enclosure. I`m not sure how much room I`ll have depth-wise, I need to get the speaker hollowed out, wind the window down & measure it. The next stage will be the rear quarters, the plan there is to pull out the useless plastic inner speaker mounting gubbins, then make an enclosure in there, & fit 8" subs (possibly slim 10`s if I can make them fit!), which`ll be powered by an amp under the passenger seat, connected to the original head units rear speaker wiring, that way I`ll have plenty of bass, but it`ll look completely stock, & I wont lose any precious boot room!
You can get a bass speaker that fits under the drivers seat. The Abarth seems to have it. They are on ebay and it's possible to improve it further. Or there's an aftermarket one that might fit under there. It's something I've looked at. A powered sub is probably the biggest single change you will make to your sound.
Honestly, I find the mid & high fine in my old 500, & even the original head unit has a decent sound, its the lack of bass from the original speakers that lets it down! I was going to upgrade the door speakers, but rather than fitting 6 & 1/2`s directly to the door frame, I was going to "hollow out" the original speakers & use the outer ring to mount 5 & 3/4`s, but I was going to box in the back to give it an enclosure. I`m not sure how much room I`ll have depth-wise, I need to get the speaker hollowed out, wind the window down & measure it. The next stage will be the rear quarters, the plan there is to pull out the useless plastic inner speaker mounting gubbins, then make an enclosure in there, & fit 8" subs (possibly slim 10`s if I can make them fit!), which`ll be powered by an amp under the passenger seat, connected to the original head units rear speaker wiring, that way I`ll have plenty of bass, but it`ll look completely stock, & I wont lose any precious boot room!
You can get a bass speaker that fits under the drivers seat. The Abarth seems to have it. They are on ebay and it's possible to improve it further. Or there's an aftermarket one that might fit under there. It's something I've looked at. A powered sub is probably the biggest single change you will make to your sound.