A Uniden 998 new will cost you the same as a roll of the dice Grant XL/ Cobra148 GTL (side mic) If you can find a nice XL/148 and you like old school it might be worth it, but you are taking a chance. The "peaked and tuned" XL/148 - to me - only means somebody has had their hands in it and you don't have a clue what they might have done. The 998/XL/148 will (should) all be 4 watts AM, 12 watts SSB. I don't believe it when they tell me they will swing to 30 watts (and it doesn't matter).
4/12 watts is more than enough to start feeding a CB amp - output is not the concern - RECEIVE is.
So let's just say a stock 998/XL/148 can give you what you need for transmit, the odds are that the 998 will be the safest bet that you will spend ~125 bucks and not have to futz around with any unexpected issues.
Radio -> Amp - >Antenna
We have talked about the first and the last is another discussion.
A radio into a KL-203 (output adjusted appropriately) will give you 80 watts very easily and does not require a whole lot of additional expense with regard to wiring. Up one level is a 2 transistor "pill" amp. This will bring you up to the 120-250 watt range and will require a little greater expense w/ regard to wiring and, if applicable, grounding and antenna. The hole goes deeper of course, but for starters the radio is the foundation and any of the above are suitable, it's just a preference as to how much a risj you want to take and how much you want to spend. "BIG Radios" are often wasted later downstream.