Power Handling, RMS: 90 Watts Power Handling, Peak: 270 Watts Sensitivity: 92dB Frequency Response (±3dB): 49Hz - 21kHz Mounting Depth: 2-7/16" Mid/Woofer, 1-1/4" Tweeter Impedance: 4 Ohms
i guess i need an amp then. right? will it sound even ok with the 18x4 rms hu i have? how will it be to install? would a 6.5inch give better sound? would a 6.5 inch one fit in my 6x8 slot?
infinity makes some really good speakers. you'll need an amp that will put out 75-100 watts to push thoes and make them sound decient, more would be nice. the 18rms would underpower them, wouldn't sound that great. i think a 6.5 inch speaker sounds better then other sizes, but sound is usually a personal preference, listen and see which you like best. you can fit a 6.5 in a 6x8 slot using an adapter plate or just a piece of MDF.
at cardomain.com, there was a significant difference in bass response between the 6x8 comps and the 6.5 comps. the 6.5 comps were much better. ive also heard circles are much better for bass than ovals... how tru is that?
it also says that the Infinity KAPPA 60.5CS have a RMS of 90 Watts... wouldnt 100 be overpowering them? if not... heres an amp i found:
Profile California AP600 RMS Output Power(4 Ohms)-100W x 2 75.00 descent quality?
Generally, comps should be powered with 75-100% of their RMS handling value. Don't overpower them too much if at all. circle comps have better sound quality = SQ, but oval comps are louder = SPL. 6.5 will not fit into 6x8 spaces unless you do cutting and custom work. Think about it, your spaces are six inches high, but you need 6.5 inches. Width wise you are fine and room to spare but not so in the other direction. 5.25s should fit fine provided you have enough mounting depth available.