Wow $1500 is a lot, but when you think of how much it would've cost you seperately, it ain't that bad. I don't think the thinner gasket is a MUST but a stronger one is definitly prefered just like the timing belt, for insurance. And the stronger gaskets are usually thinner. Which could be good or bad. It would bump up compression a little which would make even more power but it could like I said before make something else inadequate and need to be upgraded, like fuel or spark concerns. I wouldn't know exactly where to get it, I haven't searched for it.
And I would also get an MSD ignition system. It doesn't cost that much for what it could do for you. Then with the capabilities of the system, you could try 89 octane and play around with the MSD timing to see if 89 is enough for what you want. But if the only way it doesn't knock is with 20 degrees of retard (example), then yeah I guess 92 or 93 would be in order. It's all about tuning. I'd also definitly get a A/F ratio gauge to make sure you keep the ratio within check and you don't blow up your "brand new" engine. There's probably something else but that's all I could think of right now
