With all of the times Ive added to my system, do it once and do it right. When you get into 6 speaker systems, a DSP is not mandatory but I would suggest it.
Do you want to go with co-ax, pro audio speakers?? Where do you want to put the amps? You doing the install yourself?
Need to listen to as many bike systems as you can and figure out the sound you like, then go from there.
Piece together your system to maximize dollars and quality.
2009 Road Glide. 16 in Vindikta Wild Cats. Aquatic AV, Stinger 700X4 to MMatts, Audiopipe horns.
6900pros in the lids w/ sspn.4 1000d, tuned with DD Audio DSI-2. S&S 106, lifters, push rods and AC. Drago 2. CycleRama 575. Progressive monotones -1in. 12in. HD adjustable rear shocks. Painted inner fairing. Tuned with TTS. Blacked out!