Advice on Dedicated HT Setup

[JonathanG]

Hello All,
I have been a lurker/reader on this site for over a year and this is my first post. Naturally it will be a question.
I have a new dedicated HT room with a front projector and a 98" screen. The room is approx 14' x 29' bonus room above the garage. The screen is on one 14' wall. Currently I have a 7.1 setup consisting of infinity 150 rears, 6" in Walls for the sides, an infinity center, some older JBL G series towers in the front and a 8" polk sub. All powered by a Pioneer 816 (but I may move my panasonic xr55 in there).The rooms ceiling is shaped like this /-\ if that matters much and room is fully carpeted.
My question is do you think the CBM 170's would be enough for front left and right? Do you think it would be an improvement over the towers I currently have? It sounds decent to me now but I have been wanting an excuse to try those 170's and with the b-stock sale, seems like a perfect time.
I would also purchase a 340center to match. As far as subs go Im thinking the STF-2.
The setup is for 100% movies/HDtv and considering I also want to replace the weak sub, my budget is a little tight.
What do you think?
Thanks

[Mike^S]

Thats a pretty big room. I think the 170s would have a little bit of trouble trying to fill it, especially if you like to play at loud levels. I think it would be worth a try and you could always move them to the back and get some 340se for the front.

What type of improvement are you looking for? The 170s are most likely clearer and more detailed than those JBLs. But like I said, a small bookshelf speaker is not going to fill the room as well as a big tower speaker.

[curtis]

It also depends on how far away the listening area is from the speakers and sub.

Like Mike said, it all depends on what you are looking for.

[JonathanG]

The seating area is 14' from the screen. The sub is about 6' from the seating area. Like I said i have a 7.1 setup with the rears all the way back on the back wall.
I guess im just looking for a better sound. one reason would be a better quality speaker. The other is the fronts and center would be timbre matched.
And of course im confident going from the polk sub to a STF-2 would be a huge upgrade.