I am a novice who's trying to replace the shutoff valve underneath my kitchen sink. My water flow is and has been really slow for a long time. What type of shut off valve do I need to get? Straight Valve? 1/2" to 1/2" or 1/2" to 3/8"? And is it best to replace the water supply lines to the faucet from the water supply pipe as well? Please advise. Thank you! Please see picture attached.