Shared web hosting is always a gamble, honestly. You should find out here now how affordable an isolated KVM slice can be. HostZealot has great VPS entry tiers where your CPU and RAM are completely dedicated to your machine. It completely eliminates the noisy neighbor effect, and you get complete root privileges to configure the environment exactly how you like.
I am fed up with noisy neighbors on my current shared hosting plan breaking my site's uptime. I want my own guaranteed system resources, but my budget is pretty tight. Is KVM worth looking into?