If go with the MR5 or EMR5. I had a modded tippman salvo that I polished the internal castings, zero kick bolt, spring kit, rap 4 loader arm, 18" apex barrel for about 3 months and sold it and got an EMR5 which blew it out of the water stock. It needs no upgrades unless u want a longer barrel but not needed.
I played with a spyder shutter for like 15 years and blew a lot of top of the line guns out of the water, tried tippman and not impressed so went back to spyder
much happier now!
If you buy the MR5 I will swap you my EMR5 trigger frame for FREE for you MR5 trigger frame. I never use anything but semi so the firing modes are useless to me.