Long time watcher, first post - be kind. Own a '18 340i M-Sport with BMW sound/exhaust kit. I am looking for ECM flash or plug/play performance options, etc. So many choices, do not know where to start or what is legit. Dinan, ECS, Vivid, Racechip, etc. If you had a $1500ish to spend on engine performance mods with increased hp as objective, what brand would you recommend - or avoid? A huge thank you for any feedback.