Likely to brake a stud or bolt pulling header on 92 miata engine?

I have a nasty oil covered 1992 miata engine out and on a stand.  I have already gone through many cans of brake cleaner.  Thinking about removing the header just to clean better.  Is there a big risk of braking a stud or bolt?  This is going into an exocet when It's clean and the header will probably be coming off in the future for a FM turbo kit.  I am torn about doing something that might cause the exocet build to go even slower and biting the bullet and solving the potential header removal problem now.  Thanks in advance.

When I put a header on my '90 (also leaky and had about 120K miles on it) I didn't break a single stud or round off a single nut. I started soaking it in PB Blaster twice a day (when I got to work and when I got back from getting lunch) a week before I did the header swap. The studs are pretty beefy, so any where the nut was seized to it, the stud just unthreaded from the head.

Anytime I'm doing exhaust manifold I follow the tighten just a smidge before loosening rule. My success rate has gone up greatly. 

Yeah, you're more likely to pull a (steel) stud out of the (aluminum) head.

Keith Tanner said:

Yeah, you're more likely to pull a (steel) stud out of the (aluminum) head.

And then you just thread it back in like it's a bolt, while taking car not too strip the head out from overtorquing. Seriously, Mazda went overkill on some of the fasteners on these cars. The exhaust studs are pretty beefy. The bellhousing has, what, 11 bolts and they are all pretty large.

I've never broken a stud on a Miata engine while removing the exhaust manifold. 

Fantastic!  I will start first round of pb blaster today and take it off this weekend.

thanks everyone!