96 outback 2.5 HG work

my uncle and I are going to replace the head gaskets in his 96 outback 2.5, we've
done some research, and found some great tips are are sure we can do it, there's
a few things we can find though.

first, does the engine have to be pulled to do this? I read somewhere that the
cylinder head bolts hit the engine compartment before they can be pulled out all
the way. has anyone successfully done this? would it be possible to drill holes for
them to go out? we're both pretty mechanical people, but we're not mechanics.
would it be easier to pull the engine and do it, or leave the engine in? it's his car
and as far as i know, he doesn't plan on replacing anything else other than
necessary gaskets and such.

also, when he talked to a mechanic, the mechanic recommended buying a new
bolt set for it that costs around $300 dollars. this seems ridiculous to me. is it
just me, or is it actually something that is recommended?

any help is much appreciated, thanks.