Welcome to AF!
The only problem with the VTEC-Controller is that it has to be dyno-tuned correctly otherwise you might become a lot of trouble with it. And itīs not really worth it unless youīve done some other stuff to your engine. The best one seems to be the Apexi VAFC though itīs kinda expensive IMO.
Another thing you should think about is what you want to do with your car. I mean an AEM CAI for example will give you better top-end power while your low-end will suffer a bit. And itīs more or less like that with most aftermarket (engine) parts.
And I think dynoed cam gears wonīt give you 10hp. Maybe half of it when youīve got good luck. Otherwise it would be a much more common mod like the CAI. But Iīm NOT 100% sure about that. Maybe itīs just like that with the Prelude!?