I'm going to get some new speakers for Christmas. I was thinking about getting these. Has anybody had these before? Do they have good sound? How hard would the installation be? I would appreciate some feedback.

infinitys have a good SQ and there are some here that have them. Installation is stright forward

As an owner of Infinity speakers in my car and my house, all i can say is that they are very high quality for a reasonable price.

There is not much bass from the 5 1/4'* as it is impossible for such a small speaker to put out bass and there is no getting around that unless it is made super deep so it can push more air but it would so inefficient and would need a huge magnet making it very unfeasable in a stock automotive application.

But anyways, i can say those speakers with a pair of Infinity 6x9'* and good clean power, you will have very rich sound with impressive bass. I dont run my subs sometimes and people still ask me what kind of subs are in my car! haha they seem shocked when i tell them it is just my 6x9'*

Also if you have the time, and want very good vocal and high imaging, mount the tweeters flush in the plastic part of the dash closest to the windsheild, not the dash itself.
I did that, and it sounds Infinitaly clear and the sound reproduction is very crisp and clear. Stereo Imagining is great too

They come with a mounting kit to externally mount, or flush mount them. You can mount them and still adjust them after to get that sweet spot.

Infinity are good, but not the best. Other competitors would be Alpine, higher end fosgate, JL, etc.

I'm not quite sure what your mean on the position of the tweeter. Do you have a picture of yours? Where would you recommend I put the crossover?

i had 4x6 comp in my buick they blew my polk back speaker out of the water but they do sound best when played loud. im getting the jbl for my back speaker and they are they same as the infinitys so they better sound as good as my old infinitys.

Whatever you do, DO NOT buy 'em from Crutchfield. You can save close to $50 by purchasing them on E-bay, or going to some of the other car audio stores and websites.
I had the older version of those speakers (Infinity Reference 505CS'*), and I loved them. Once I get back into the Car audio scene I will no doubt go with Infinity again unless I can afford some really high-end equipment.

I have infinity kappa but have owned references and they're great sounding speakers for sure!
This is where I mounted the tweeters on my car for better imaging and sound quality:

Agreed, I wasn't going to buy them from Crutchfield. They are too expensive. Were do I put that crossover? I still don't know about that tweeter placement too. Custom88, did you have to cut a whole for the tweeters? This is my first time doing some car speakers so I'm rather noobish about all of this.