I'm happy to report that they fit and can be ran off the OEM Bose amp.

I picked them up for around $140 shipped from Techronics.com and already had a set of speaker spacers that I bought for $25 a couple of years ago.

I was able to fit the Kappa 60.9cs tweeter in the OEM location by removing the cone-shaped thing on the front of the Kappa tweeters and removing one of the bolts securing the side mirror. I took a picture of the tweeter mounted, but my phone seems to have deleted it . There is a thread from 4-5 years back that detailed one person's struggles in fitting the tweeter, which was my main concern with the install.
I put some doublesided foam mounting tape on the back of the tweeter to keep it in place while mounting the sail panel. This had the added (and intended) benefit of keeping it pressed right up against the sail panel, preventing rattles.

I mounted the crossover right next to the speaker on the doorskin, securing it with a couple screws. The window switches sit very close to it in this position, so a few test fits were necessary. As a plus, the window switch panels can be removed to access the tweeter level adjustment on the crossovers.

Sound-wise, they're an improvement over the OEM speakers, no question. The sound is cleaner and crisper. Mid-bass suffers a bit and so does low end, so I would recommend installing a subwoofer along with these components. They don't sound incredible, but they are definitely an easy and cost-effective way to improve the sound of the stock system.

Next up is a set of Infinity 62.9i coaxials for the rear doors.

 

You'll get a much better sound improvement by replacing the amplifier. The Bose one probably tops out at about 60w RMS, and has heavy equalization built in.

 

Agreed. I have an extra amp in the garage that I may install down the road, just gotta find the time. The wiring harness that plugs into my Bose amp is also kinda gnarly due to my initial bootlegged splices that I did when I first got the car. I've also had bad experiences in the past with alternator whine when I've installed amps for mids/highs.

I really want to avoid running wires into the doors, but I guess I'll have to if I amplify these in the future. I've ran wires through molex connectors and it's a bitch.

In the meantime, these Kappas are an improvement over the OEM speakers and took only a couple of hours to install.

 

How are the stock speakers with more power?

I'd love to get my Fosgate 600a5 in the car to get SOME temporary boost, but is it easy to install in the trunk, replacing the stock Bose amp?

 

I bypassed my bose amp and it was pretty easy. For my JL amp input, I basically spliced the wires that come into the bose amp from the headunit, connected those to a Line Out Converter, then connected a pair of RCA's to my 4 channel amp as INPUT. Then from the same harness that connected to the BOSE amp, I needed to get my amp's OUTPUT to connect to the speakers so I got some 18 ga. wire and connected them from my Alpine Amp's output to the bose amp speaker outputs. I can take a pic of my messy install pics later if you need and draw out a more detailed diagram.

 

Good to know that the Kappa 60.9cs work with the OEM Bose amp and head unit, and that you noticed increased quality. I just got a 2003 G35 6MT and while the Bose isn't bad it's certainly not great either, so am already looking into upgrade options. I don't want to go too crazy so I've been looking into what I could do in stages. I'll definitely be keeping the OEM head unit but have been wondering about upgrading the speakers and amp, but wondered if I'd be able to get away with doing speakers first, and based on your experience this looks plausible.

 

I actually took the route you're contemplating. I added a separate amp to my Kappas about a month ago after running them off of the Bose amp for a month.

Installing another amp opens the door to many other component options so I'm thinking about selling my Kappas, let me know if you're interested.

 

Obviously the Kappas are better on a separate amp, but would you be able to approximate how much of an increase you got going to the separate amp? Was it similar to the typical increase you get going from components powered off an aftermarket head unit to a separate amp?

 

It's hard to say because it depends on the RMS wattage of the amp and the gain setting. They will play substantially louder, no doubt about that. I faded the kappas a click or two toward the front when I had them powered by the Bose amp and they sounded good to me.

 

Good to know, thanks.

 

Acr -- when u removed the bolt that holds the side mirror, was there any unwanted side effects? Is the side mirror stable, does it wobble?

After some time as passed now, is the mirror still secure and stable?

Do you think it is possible to mount the new tweeter in the old tweeter location without removing the bolt that hold down the side mirror?

I am thinking of installing a pair of Infinity Kappa 60.9cs (component) speakers in the front door of my 2003 G35 Coupe, but I have some concerns if the tweeters will fit in the factory tweeter location. I really do not want to install the tweeter in another location such as the A-pillar or lower door (next to the woofer).

If the tweeter does not fit, do you think I can cut out a hole through the original tweeter grill/screen and mount the new Kappa tweeter through this hole? My goal is to keep the look as close to the original factory look as possible.

Any thoughts, ideas or comments?

Thanks.

 

Arc -- one more question: did you remove the tweeters from their physical housing to make them fit?
According to the Infinity Kappa 60.9cs manual, the tweeter depth is 1-15/16" (49mm) deep (top to bottom). I dont think the depth in the sail area where the original factory/OEM tweeter is located is even anywhere close to that depth...?

Any info would be appreciated.

Thanks!

 

Answers are above in red

 

Answers above in red. The Infinity components have been great but I'm going with different components now that I've added a separate amp to my system. Give me a shout if you are interested in purchasing my 60.9cs set.

Let me know if you have any other questions, I hope this will be helpful for others.

 

I was able to mount the 60.9 tweeters in the sail panel location without removing the nuts (not bolts) that hold the side mirror on. I don't have a photo handy, but there's a tiny rubber protrusion sticking out of the frame behind the sail panel that can be cut off with no ill effects.

Some very minor Dremel work inside the sail panel (about two minutes each side, and you're set.

Hint...the secret is to use double sided tape to stick the tweeter to the door frame, then install the sail panel over it. This way you can mount the tweeter right up against the one mirror stud/nut that can cause interference. Trust me, there's enough room. It doesn't look like it when you first start, but there is.