I have positive stories to tell of birthing big babies!
I've had 3 - first was 9 lb 6, second was 11 lb (really!) and third was 10 lb 2.
First was in a midwife led unit, and they were brilliant. Long labour due to her being back to back, I had pethedine to help me sleep in between contractions. It was such a long labour that it wore off and then I was allowed to get in the pool. She shifted and everything became manageable. The best way I can describe it is it stopped being overwhelming pain and became productive pain. The contractions still hurt but I could feel her moving down and knew there was an end. She was delivered in water - brilliant experience.
Got on so well, the next one was at home. Did hypnobirthing and had a doula and a pool. Worst thing about this birth was that I was horrifically constipated and nothing helped, so I was pushing against a big blockage. The doula was brilliant and I'd thoroughly recommend one. No-one expected her to be as big as she was - the mw's comment was "you must have a pelvis like a bucket"... I cried.
Third one - everyone said babies only get bigger, so I was expecting to give birth to the Christmas turkey. In the end he was smaller! Also a water birth and by far the easiest birth. They wouldn't let me go in the birth centre initially, but I contacted the mw supervisor, explained my birth history, and the fact that the birth centre was 30 seconds away from theatre if I needed an emergency c-section, and they let me do it.
Anecdotally, bigger babies can be easier to birth if you are labouring upright (which I did a lot of) as gravity helps!
I managed to birth all 3 without tearing or stitches - I did have SPD throughout all 3 pregnancies, which may have helped at the birth with stretchiness. 
What really helped me with no1 as I am a control freak, was making a birth plan for every eventuality. I'm sure the mw's didn't read beyond page 1...
But I knew, and so did OH what we wanted to happen
no.1 ideal waterbirth (which luckily we got)
no.2 if I had to transfer to hospital
no.3 if I had to have an epidural
no.4 if I had to have a c-section
no.5 if the baby had to go to NICU
It just really helped me to get my head straight and I felt I had covered all eventualities. I knew that if I wasn't capable of communicating that DH knew my wishes. I was open minded in that I didn't say an outright no to anything, but I had definite preferences. Ironically I really didn't want pethedine as an option, as I'd reacted badly to opiate based painkillers previously, but it was a life saver and helped me stay in the birth centre.
Good luck - you forget about the pain pretty quickly IME and you get to enjoy gorgeous newborn cuddles. I miss those!