My stock bore 400ex is finally starting to show some signs of oil burning. Not surprised since im off the rev limiter almost religously(and the previous owner changed the oil probably a total of one time with car oil) so i expect it isnt going to take that for ever. Long story short its going 416 so i want to put in hd head studs. Here is my question and hope to find someone who has used both options.

Option 1: GT thunder (snure interlocking now) about 65.00 shipped to my door and will require the jug to be taken to a machine shop to drill and tap them for the different size and thread

Option 2: arp head studs 135.00 but they thread right into the jug with no need for drilling and tapping. I have used arp on countless car applications but never on a quad.

Thanks to anyone with info i really appreciate it!