[Tigers] Headers versus Cast Iron Exhaust Manifolds

[Would U. Believe]

I was wondering if anyone has a strong opinion about whether a Tiger is
really better off with headers versus the original cast iron exhaust
manifolds.  I think the obvious benefit of headers is the gain in
horsepower, but the tradeoff seems to be in the added difficulty in
maintaining the car, given the tight engine bay.  Anyone have an opinion re?
I'd like to have a set of the original manifolds that it seems everyone
seems to have junked because they are so restrictive.  Are there any out
there and available?  I'm just thinking that for me, regular manifolds might
be enough... I'd like to try some out.  Thanks.  M