Blakcard has a good point about adding a DSP while not changing the speakers. Dynaudio makes some good speakers, no doubt, but I've never seen the ones used in the VW's, and it's very possible that they are junk and nowhere near the quality of their non-OEM speakers.
I really don't know. I'd have to see the dyn speakers in person, and ideally give them a listen. A DSP can make any speaker sound better, I just wonder what the limits are for the OEM Dynaudio speakers, and whether or not the improvement from adding a DSP will be worthwhile. If you're interested in a project, and maybe a long term hobby, then add a DSP. If you want to improve your current setup a decent amount and move on, then I'd recommend against it.
Also, I specifically designed a built a slanted box like the one you are planning. I wasn't interested in doing a fiberglass enclosure in the wheel wells because I wanted to port the box, and porting irregular fiberglass boxes is a mess. I thought about the spare tire well, but I've had too many flats to ditch the spare, and I didn't want to raise the floor for a crappy shallow mount sub. The box is easily removable, about 1.6 cu ft tuned to 28hz, for a 10" sub. Hatchbacks are easy to get great bass from, so it's plenty of bass to sound really good
I really don't know. I'd have to see the dyn speakers in person, and ideally give them a listen. A DSP can make any speaker sound better, I just wonder what the limits are for the OEM Dynaudio speakers, and whether or not the improvement from adding a DSP will be worthwhile. If you're interested in a project, and maybe a long term hobby, then add a DSP. If you want to improve your current setup a decent amount and move on, then I'd recommend against it.
Also, I specifically designed a built a slanted box like the one you are planning. I wasn't interested in doing a fiberglass enclosure in the wheel wells because I wanted to port the box, and porting irregular fiberglass boxes is a mess. I thought about the spare tire well, but I've had too many flats to ditch the spare, and I didn't want to raise the floor for a crappy shallow mount sub. The box is easily removable, about 1.6 cu ft tuned to 28hz, for a 10" sub. Hatchbacks are easy to get great bass from, so it's plenty of bass to sound really good