your experience is like a friend of mine....he had never had a snowmobile, then got a 580ext. That is a pretty big and powerful sled. Which it only took him 3 days to roll.
Another friend of mine had just as powerful a sled, but he had owned a 250, 340 before. so he worked his way up.

You started on the high end of performance. Ive had the earthquake 8e which has basically the same performance and I know these things can haul.

I personally do not like to upgrade suspension arms to alloy. Generally, plastic arms will flex enough to absorb most impacts. A alloy arm wont flex. This puts added stress on the chassis where the arms connect. so, id rather have to replace a plastic arm then replace the chassis where the arm attaches.

Sometimes a shock cap can just come loose. other times the bladder that sits inside the cap can tear. Either can cause the shock to leak. If you remove the shock cap and the bladder looks good, just add some shock oil and tighten down the shock cap.
Shock oils are rated by weight. many 1/10 models use 30w. The redcat may use the same, as they often have oils lighter than what would be best for them. there are shock oils made by different brands...as far as I am concerned they are all the same quality. A small bottle of 30w will be around $10 and will usually fill 4-8 shocks. The flimsy feel is because there is not enough oil.

this vid shows how you refill a shock: https://www.youtube.com/watch?v=ybHDV4iGIFU