If your motor still has the original stock bolts, replace them with ARP studs. It'd be smart to replace them anyways, but the studs price is a wash against bolts so why not upgrade.
It's my impression that the stock composite gasket isn't limited by power levels that much. It just lessens your room for error on your tune. The Mitsu MLS is far stronger and resists knock and such, so it widens your window for tuning.
A composite gasket will also conform to an uneven head and block surface better as well. If you're not machining the surfaces, don't get a MLS.