On your '94 CBR...maybe. Depends on what else you intend to do to it. If you open up the exhaust, then you will need to open up the intake. Then you will need to correct the fuel mix. This is done by either remapping (on fuel injected bikes) or rejetting (on carbureted bikes). In this case, you could probably gain fairly substantial power. Just adding the full system without any other modifications could actually hurt power. You might even want to consider simply regearing to make the power delivery match more closely what you need.
On the later model bikes, especially "hyper-bikes" like the R1's, the CBR929's, GSXR1000's and even the full on mid-sized sportbikes like F4i's, R6's, GSXR600's, GSXR750, etc. they are already running fairly close to the HP potential for the stock internal engine configuration. Therefore, every extra pony you squeeze out of them comes at a price. You can do away with the EPA "lean spots" with pipes, filters, remaps, etc. but you only gain a few HP with these mods. If you really want to get the extra HP from them, then you really have to be willing to spend the money with internal engine modifications, like freer flowing heads, different valve angles, reworked cams, different pistons, etc. It gets very expensive and the reliability goes way down. Full out race bikes have to be rebuilt after only a very short running time, or they will grenade. Some of them after every race. Also, you can affect the "streetability" of the bike by trying to wring too much out of it. Who wants to keep the engine in the 10,000 rpm range all the time on the street? If you spend all that money on Hp you want to use it, right? It's usually all up top on the really high performance engines.
Remember that making your bike faster won't necessarily make you faster. The first step to making you faster is to fix your suspension. Simply having your stock suspension properly adjusted for you and your riding style will make an incredible difference. Then go take a track course. Once you know how to use the (properly set up) power you already have, you may discover that you don't need any more.
A good slip-on won't gain a lot of power for you (if any), but it will sound better, and it's a lot cheaper than a full system.