Cyclops

Hello! I've become an airsofter relatively recently and with my vast inexperience and small budget I ended up buying an ICS MP5SD5. Now I have been told by multiple people out on the field and my local airsoft store employees that it is a rather old replica, and while it was good for it's time it has long been surpassed by modern replicas. However I also got some feedback that upgrading it is relatively easy and it can make the replica quite effective on the field. So, I have come here to ask how should I upgrade it, mainly what type of components I should buy. Bear in mind my replica is completely unmodded, and I have near to none experience in this field, I only do regular maintenance to clean it and service it in between games. I am primarily looking for a smoother more responsive trigger (maybe due to it's use it has become slightly shaky and inconsistent), higher rpm, slight increase in fps and anything that might reinforce it's internal components or make it more resilient to wear and tear, especially that firing mode selector. Thank you in advance! Cyclops.