You can replace the BOSe speakers with any I think.
I had read differing information, but eventhough I told the shop to rewire my speakers to my headunit-they didn't and left them hooked to the BOSE.
The impedence was differemt, 4ohm v 2ohm BOSE-but I never had any problems, and the Pioneers I had for 3 years sounded REALLY good. People always thought I had a sub and didn't
I have the same 6.5's I used in my Leggy for 2 years, I'll sell em for $30 + shipping.
Let me know if interested.