Roll the dice for 10thou more miles with 02 Lesabre?

This is a followup to my first original Q re my 02 leSabre.  Yes, thank YOU I have read that "At 91,000 you're right at the point where the intake manifold gaskets fail"--and I DO wonder what the going $ rate oughta be for that?! Does that require opening up the engine and extensive labor$$? Since it's gaskets, ie rubber lining to stop leaking, and they ARE failing, will they eventually just--ugh-totally fail and what then, ?, all the oil sprays all over the engine and...I just had the lower control arms in front replaced (freakin speed bumps!) for $600 and had the first-ever synthetic oil--I 'feel' like my Sabretooth maybe doesn't like synthetic? and I would LIKE to get about another 10 thousand miles out of this Buick. I got in in 2005 for 10G with extended warranty 3yrs/36000miles and it has worked out well. In 2018, will have $ to put another 10G into a Buick with 45G miles on it, Glad for any and all replies--this is way more interesting and intelligent conversation than the dating website pof dot com. ha ha But I need for the car to be reliable, as I am a Special Needs attendant and it is transportation and even with Allstate towing I don't wanna be at the side of the road. Thanks!!