Hey, I need to chime in! I don't like oil restricting pushrods because your springs need that oil. Plus, you're not going to go to roller rockers, so you could increase the wear of the valve guides. Even though you will get a GT cam and springs, your engine won't need to change anything like how strong the chain is, how strong the pushords are, or how much more oil you need on the lifters & cam. The stock amount of oil should be sufficient since people with many, many more mods are running stock rods and have no oiling issues of which we're aware.
Basically, you should change the timing chain. I like the stock one because an aftermarket replacement is $80 for a JP and $100 for a Rollermaster. The stock timing chain is $16 from ZZP. Rollermaster has said that their single roller timing chain is a stock replacement, and you should go to the double roller to prevent the chain from breaking if you modify your cars. No stock timing chain has so far broken, and people like 1337ssei are running 105# springs and 1.9 roller rockers (yes, w/ oil restricting pushrods) on a stock, never-changed timing chain.
The GT cam has a .507"/.507" lift with 1.6 rockers. A stock cam has .346"/.365" lift with 1.9 rockers. For the extra 14-16 hundredths of an inch of lift, I would recommend refreshing the stock timing chain, but you shouldn't go with an aftermarket one that'* meant simply to replace the stock one. I do understand that Bill is running quite the awesome setup with 130# springs and that Intense says the JP hasn't broken for them, but ZZP says it has, and someone I guess said the Rollermaster double roller has broken as well. Ultimately though, no one says a stock timing chain has broken with a couple mods like rockers or a cam.
My 99 is hopefully soon getting torn apart and will have a top swap to a supercharger, intercooler, cam, springs, heads, shorter pushrods, etc. I'll be using a stock timing chain since really our chains are pretty good and can hold out just as well as any other single chain from another manufacturer, even with 5 or 6 times greater costs. If you're worried about something breaking, it would be a valve spring from a lack of oil due to oil restricting pushrods.
94 STEi and 99 SLO