Untouchable. HSP makes the best parts around hands down. Personally, I have ran all sorts of parts from K&N, Sinister diesel, MBRP, and many others. HSP is by far the best, currently running their intake system, intercooler and y bridge, and getting ready for their coolant tank, radiator line, thermostat housing, and trac bars. Great build quality, nice sound resonating, and custom colors to top it off. Run their setups on a couple of our duramax trucks doing everything from heavy towing to drag racing and their products don’t waiver a bit. Can’t recommend these guys enough, especially Mike for his non-stop hard work and dedication to customer satisfaction.