All QEV's, require modification, to teh gun, if you want to be able to service it.
Some QEV's, (liek teh Planet ones) require you to dig out part of the body, to fit them...this looks messy.
In order to access teh bolt, you are required to slide off teh outer shell, which you cannot do, with a QEV installed...so...you cut a section out, towards the front of teh gun. If you do it carefully, you can simply slide this back in, and no body is teh wiser...teh alternative, is to remove teh QEV everytime you want access to the bolt...not clever, or practical.
FACT: If at some point in teh future, an uncapped, or VIRTUally uncapped board is released for the ION...your gun will shoot down, at high rates of fire, if you do not fit a QEV or other mod...teh QEV will allow teh marker, to CORRECTLY cycle at rates upto around 26 CPS...
I have fitted my QEV's in several IONS, and have experienced no problems...the guys using these Ions, were actually complimented, by an SP Sponsered team, using Ions, at how well their guns shot.
I am not aware of any excesive wear on Bumpers...but, so what if they do..its only a bit of rubber, who cares if you have to replace it once in a while?
Right Hairbear?
They do fire more shots per fill...teh QEV will allow you to drasticly reduce your Dwell...from 52 bleeps to around 8-10...a poo load in otherwords.
Oh...and they do seem to kick a bit less I think...might be Placebo effect...but.../?????