i have one from a previous car and wondering if it will work on my evo

 

i just put that on my evo...
works good... is it the high performance one
i got that

 

yeah its the high performance one.how well it hold boost and what psi you running

 

I am using the same one right now, it works well but the boost does still taper about 1 bar/2PSI no matter what boost you set. If I set it to 21PSI at 4K it tapers to 19 at redline, 19PSI at 4K tapers to around 17. It's still much better than stock, but not quite what I was hoping for, and yes I read the manual and set it as recommended. I even tried taking the supply pressure from the throttle body as they recommended, that made it even worse for some reason. It also tends to over shoot the boost some what at high gear/low RPM.
MBC's are simple, reliable, and cheap, but they simply cannot maintain a set boost value over a wide variaty of conditions like an EBC can. It's just a fixed bleed pressure valve, what did you expect?
It does seem to spool faster than the stock EBC though.