Originally Posted by VooDooPeteK
personally if the spring is the only thing you are going to change I would say go with an m90 spring, the aftermath hop ups units are crap as well so you might want to look for a replacement so you can use a normal aeb barrel
but yea m90 or m100 at most in those from my personal experience
Agreed with the M90. Replace the hopup, selector switch & selector lobe (I replace these a lot in my shop) and possibly the trigger switch.
Barrel is ok for CQB where long distance accuracy isn't really a factor, but don't expect much. The rest of the gun is ok at best. I see the Aftermath MP5 series a fair bit in my shop for a variety of issues, the above being the most common.
, seriously, get AV'd or visit one of the site supporting retailers. There's way better out there for what you'd pay for a Broxa/Lycaon plus the upgrades. If you're a tweeker and don't mind spending the time and money needed, you can work wonders with a Broxa/Lycaon but there's way better platforms to start with that would be way cheaper in the long run.