That all depends on what you're trying to accomplish. Aftermarket intercoolers usually do two things: cool the air better, and flow more air than stock(highly oversimplified explanation but that's the basics). So if your trying to maximize your performance, yes you should do both and remove all of the restrictions in the system. If you just want the extra power and don't care about achieving maximum results, simply stick with the down pipe and forget about the front one. If you really want to maximize it horsepower-wise, you should do all of the above mentioned in as well as a water methanol kit. Before you do anything I would decide on a tuner first. Your stock intercooler probably really isn't being pushed all that hard since you have no tune and upgraded the exhaust already. Some of it comes down to your location as well. I live in the desert so I always try to maximize my cooling performance.
