Someone correct me if I'm wrong, but can too much timing cause problems with the head stretching the head bolts? If so, where is that point at that it begins at? 19*, 21*?

 

Yep.
15.5° is the limit...... Just kidding after I saw 16° in your signature.

You'll get various opinions on the timing advance limit where peak combustion pressure lifts the head stretches the bolts and vents the head gasket. Past 17° is where you will probably have problems with stock gasket & bolts and large boost. You may go 1,000 miles or 100,000 miles

 

what about boost levels under 45psi?
Oh, by the way. you got me for 1/2 a sec. with the 15.5

 

With a stock turbo your pushing time on your HG past 40psi...without messing with timing. Its wayyyy out of its map. With a S-300 based trbo (depending on size) you'll be ok with 16.5-17*. I ran an HX55 on my 98 for pulling and at 17* timing, and ran it with the 35 on the street, its held up for about 100K miles so far, just waiting for it to go so I can ring the head and put on a nicer gasket. If its your only mode of transportation, leave it like it is unless you like rentals and spending money, sooner or later it catches up with you.

 

At what point would you need to go past 17 timing? 500-600 hp?