Looking for help with a Simple Tone Generator Project

Alright, Excuse me as this is my first post, I did some searching around and noticed several subforums, but figured this was the right placed to post a guidance request question.

I'm looking to accomplish a rather simple tone generator with an LCD screen, but instead of having a speaker, I'd like an RCA out, in order to push sound to a car amplifier. I won't to be able to control the Hz and Volume via momentary buttons with the software, and I'd like an Led status indicator and an on/off switch. Most of this I have the common sense to figure out, and looking at the code examples, programming will be very easy (it's my strong suite), but I had a few specific questions.

1.) What Arduino board should I look into getting?

2.) Do I need a serial LCD in order to save port usage of my arduino? I'd like to not buy a bunch of shields.

3.) Is using an RCA female jack as easy as removing the speaker from a schematic and replacing it with the Jack?

4.) For the purposes of testing the amp at different Hz, will using the Tone() function suffice? I don't care about sound quality, but it's always a plus.

Check on this link: http://didier.longueville.free.fr/arduinoos/?p=64 1. any 2.? how many pins do you need? LCD sometimes work with 4 digital, half-words 3. yes 4. yes, but R2R way allows to control level and freq, other option external DAC. (SparkFun is best friend)

1) pretty much any

2) yea how many pins do you need, your going to need a nibble (4 bits 4 pins) and a couple more for lcd control, couple push buttons and a pwm out, should be no problem for a normal arduino and a (much much cheaper) LCD without a serial backpack

3)mostly, line level audio in is 0-0.7 volts maybe 1 volts tops, arduino puts out 0-5 volts, might need a couple resistors to cut that down so you dont overdrive your input

4) low frequencies will be pretty clicky with raw tone output so some filtering might be in oder (see what i did there hehe) I would start off with a crappy little speaker and test it out before you go hooking it up to a "1 dollar per watt 3500 watt jackhammer", it may fall within your test requirements, otherwise filters are not horrible to make