B5 Classic, MegaSquirt has been around since 2001. For a long time, that was the choice of ECU for the Drag Week guys because you could build the box yourself and build in your own features. You can make it exotic or simple, and either way it costs far less than a Holley or similar setup. There is a MASSIVE following and awesome support either from DIYAutotune or on the MS forums/groups. The support isn't getting anything but better every day. I personally use an MS2 Extra ECU and it has all the fancy stuff that Holley, FAST, FITech, Mopar, etc have. Auto tune, customizable VE and AFR tables, AE enrichment, all the bells and whistles and it cost me $750. The MS3 Gold Gold Box and Harness kit was made specifically for the Hellcat. Remember that Mopar especially has to get their 400% markup for anything they sell.