Thinking of getting a 97 SSEi , Will I have to put high Octane gas in it???

yes, you should use premium unleaded. I use 91 octane here in Arizona. I know some of our members can get higher octane than that.

For an SSEI the higher the better. I would use 93, but that depends on the miles on the car. If they are high, use 93. Otherwise the car will knock, killing the engine.

DEFINITELY use a higher octane gas. And using a lower octane with a bottle of octane boost won't be sufficient. The higher octane fuel also has necessary detergents and other ingredients for higher perfomance engines. Now, using a higher octane gas with a bottle af octane certainly won't hurt if your SC'd, and shouldn't cause detonation.

Heck, I use 93 octane on my SSE. Burns cleaner and more efficient.

The short answer is yes you need to use 91+ octane gas in a SSEi. I could get into the long answer, which ends with it isn't required, but that also requires mods and a few other things, so unless you fork out big bucks for mods you have to use Premium unleaded.

It doesn't burn cleaner, if you're talking about cleanliness.... This is one of the biggest myths in gas. It does "burn cleaner" and it'* more controlled though. You also have nitrous and some other sweet mods (I wish I had, i'll do the never ending quest for the 2nd fastest L27)....