You will see some gains
Nothing major but if you are familiar with the engine and car the way it is now...you will notice an improvement...The heat thing is too hard to factor in...If you live in an area that is warm during the day and colder during the night...that can make the difference in heat soak....at 50* the intake will be sucking much cooler air than the same intake at 90*...and that can make a big difference...which would make a difference with the stock intake too...
the only real benefit to the SRI is the filter element, which is much better than stock, and the larger area is displaces...it can suck in much more air, regardless of temp, than the stock intake overall...Don't expect massive gains, but regardless of temperature you will see 1 or possibly 2 with the intake alone...
The total gains are unknown, mostly becuase of that exhuast...I know nothing about it...The website's flow diagrams make it appear to be extremely restrictive, but who know on how valid those diagrams actually are...And remember in the automotive aftermarket there is no such thing as "too good to be true"...that website makes that muffler appear to be "too good to be true" which is reason enough for me to stay away until it's validity is proved...