Pre-amps are only useful if you have a deaf receiver or a lot of feedline/splitting loss. Keep in mind they amplify both the signal and noise. Not only that, they add additional noise (this is why the
noise figure of the amp is important). If you decide to use one then make sure to get a mast-mount amp, as its better to amplify and "push" a good signal down from the antenna end of the feedline as compared to trying to amplify a degraded signal at the radio end of the feedline.
If your issue is feedline loss then you are better off investing in better coax. If its signal level then buy some mast and get the antenna a little higher. 10 more feet at VHF can be a world of difference.