A side gapped plug is a good easy cheap mod that can be a good benefit, I have been doing it since my old motocross days.

I used to do this to my cheap plugs and get the performance bump without buying a spark plug that costs 3 times as much.

There is one draw back though, a side gapped plug will foul easier than one with a standart gap, the reason is there is considerably less area available to spark to than a plug with a standard gap, thus making it less forgiving to being "gunked up". It's not a major problem though, just make sure the engine is tuned properly