prob a stupid question but can u adjust the trigg on the 5.0?. The best upgrade is a barrel set but thats if u want to spend alot on ure 5.0 instead of saving for a higher end marker but the jt isnt bad.
If your happy with the JT for now then get a good air-system that you can use with a better marker in the future, and if you go for an expensive barrel get something like the freak so you can change the back section at a later date.