I am no expert, but i had a Pipercross Viper until today and thought it was pretty good for what it is! I have had spoon drop-in, AEM V2, AEM CAI, Mugen, Pipercross Viper and now ITG Maxogen (in exactly that order)
I must say that the AEM CAI gave the most noticeable gains in torque at the time, jumping from a V2 to a CAI. However, the V2 gave me big gains (once the car is moving) over stock, esp in VTEC. The biggest shocker out of them all was the Viper tho! For the price and the fact that you wont be sucking up water everytime it rains, and pooping urself when u see a big puddle (the reason why i removed the CAI) it was not too bad! Although a bit noisey, the gains were good i thought! It gave some nice mid range torque and VTEC pulled hard, i would say it isnt far off from the CAI, def better than the Mugen (shocker)!
From what you have said, you are directing ur airfeed to the front of the car? This is where u might be going wrong, as the filter faces the back of the car, you are turning the air feed 90degrees to point the air feed through the engine bay back to the front, behind the radiator!
Try reolcating the air feed to either point towards the bottom of the car (straight down from the end of the filter) or towards the passenger wheel arch (i had mine here). The air should be colder and also has less distance to travel along the pipe, so you might notice a harder pull? Give it a go and see if it makes any difference, but like i say i am no expert. I was surprisingy impressed by the pipercross with the air feed located towards the wheel arch and think its not a bad filter. However i have now got the best of all worlds with an ITG, hopefully i will notice even better gains when it is run in!
My other mod is an exhaust, i have the Tanabe SMR system (jap high flow exhaust) and i must say, i felt the exhaust gives good gains combined with the air filter! If you want greater sound and more mid-range/high end power, get yourself an exhaust. I have not had any handling mods as others have mentioned, however i dont think this is required until you are familiar (and can utilise the existing firm setup) of the way the car handles anyway, as you wont be ready for it
The existing setup is very good and fun, however an upgrade im sure would make it that much better!