http://www.hrvforum.com/forum/409-electronics-audio/15130-lx-new-stereo-installation-done.html

That thread is probably a good read for you. I have the EX and haven't messed with mine personally, but have done a little aftermarket upgrading. 14 gauge wiring is probably good, I think 12 would be overkill.

 

I changed the soundstage on my exl by putting in Alpine tweeters on the doors. Drastically improved the sound.

 

I appreciate the feedback. I have used the search box on the forum using tweeter, amp, speakers as keywords and read those threads multiple times. I learn something new everytime I reread the threads, but... I've still yet to see if anyone found a tweeter that would fit in the clips on the underside of the dash grill covers (and what brand/model).....or....how has anyone braced/bracketed a tweeter that does not fit in the OEM clip to the dash?

 

I just installed a set of JBL 600C in front, and the same JBL 600C in the rear ( without tweeters) - the OEM tweeters are not plug and play or clip in- i had to do some fab work -BUT it came out great.
i trimmed the flange off the tweeter and it was the same diameter as the housing in the OEM grille piece- so a little crazy glue to hold it in place, and then some epoxy all around worked well- its fit int he same dimensions and space as the factory did.
I had to make my own plugs from the OEM tweeter cut off surgically with a dremel etc- again stuff i had done before so i was confident it would work. Nothing will fit from any aftermarket speaker maker in these tweeters.
AND- the curve of the grille (to match the dash) does not give too much flat space to put a flush mount tweeter either ( that was plan A, and that got scrapped )- plan C was a surface mount tweeter.
I will post some pics.
I did send Sunday morning getting this all finished, and added sound proofing in all the doors too- so far the factory head unit can be adjusted well enough that i can hear a def difference in sound with all 6 speakers now replaced. The woofers have about 3 weeks of play in them and they have appeared to loosen up and sound better. The tweeters have about 2 hours of play on them.
A new head unit was on the list- but I may not need it now. the JBL components were cheap- and that is a bonus.

 

 

Bit of an older post here, but excellent craftsmanship on the wiring/harnesses!

 

Found a company called Red Wolf (only on Amazon....), they makes these tweeter connectors - perfect fit for the Honda OEM wiring harness.
Now you can bench wire ( and test) new tweeters and have a plug and play type replacement.
if you keep the old tweeters and dash grille- you can save them as a back up or even quick swap out if needed.

 

I tried the Red Wolf adapter posted by John35g and they fit perfectly even though Red Wolf doesn't list it as fitting HRVs. I picked up the JBL 601CF from Crutchfield. They sound great. These came with a crossover which was a bear to install. It requires connection to the door speakers, tweeters and receiver. Crutchfield was unable to help me in finding where they spliced together. In taking a lot of the dash apart I discovered the slices are actually in the interior side of the plug going to the door, near impossible to get at and spot to put the crossover. The easiest option I found unless you want to take the large wiring bundles apart (the driver side is almost impossible to reach) is to run new wires to the tweeters (not splice in the existing connection, but a connection to the tweeters only and leave disconnected from existing wire) and cut the front speaker wires behind or near behind the receiver and connect the crossovers. Feed to the crossover from the speaker wire you cut (each side) coming from to the receiver, the door speakers (woofer) from the remaining side of the wire you cut, tweeters from the new wires you ran to the tweeters. This will save you a lot of time and heart ache.