if a terrier bitch that has a harsh wiry coat is spayed will this change the texture of the coat or will it remain the same if you keep feeding the same , and hand stripping the coat out,
also if the coat has been clippered instead of hand stripped how long will it take to get it back to normal with stripping it instead of clipping it the bitch is very young from what they where saying about 6 months old

The side effects of neutering is in the lap of the Gods, some will change some will not, but it is mainly those with double coats that have problems. Would say that coat change is not too much of a problem unless you show and that dogs seem to have more problems than bitches, the most noticeable problems with bitches is loss of body shape and incontinence. Reduce the amount of food, keeping her slim in important in maintaining normal health.

Like Nova says, eveyone is different.
When my bitch was young, I had to clip her coat really short as she had a fungal thing on her skin that needed treatment but after we stopped the treatment, I let her coat grow in.  I would say that it was about3 months before I could start getting some shape to it again(handstripping and scissoring) and about 6 months till she was in full, normal coat.  Her coat returned to normal but she wasn't spayed.
Another bitch, her owner had been clipping the coat but upon seeing my girl growing it back, she felt like doing the same with her dog.  After about 8 weeks, she brought the dog to me as instead of growing down, the sides had been curling back up.  I told her to persevre and see if some weight would take the coat down and I even dried her with a flattening towel but still the sides curled up.  After another month we had to admit defeat and clip her coat in. 
She was spayed.
The coat had a fluffier texture and even oiling, etc never made any difference.
I recently got my 10 yr old bitch spayed and I have noticed a change in her coat allready.  It is much drier, thicker and curlier allready, more like the second bitch I was telling you about and it's only been 6 months.
I would say any dog I've know to be spayed has a different coat, just feels a bit drier.  Kind of like when we bleach our hair? Goes cotton-wooly?

It is also very breed dependent.  In my own breed the difference would not be noticeable to a casual observer.

I personally find the coat becomes less waterproof in my double coated breed, and a fraction softer.

If the coat is really good texture (in my breed harsh top coat soft undercoat) then it will largely stay that way.

I have a 12 1/2 year old bitch who has been complemented on the superb texture of her coat last weekend and often before, and she was spayed 5 years ago.

It does seem that some types of coat are very negatively affected by neutering, such as Spaniels and setters who have a silky top coat and flat undercoat.  These seem to grow huge cotton like under coats and the top coat looses it's silkiness and goes curly and they become difficult to groom.

I believe similar things can happen to terrier coats.

I think the age they are when spayed/neutered can in some breeds, make a difference. My terrier x who is stripped was done at 18 months and his coat is a little longer than it was but still strippable and its nice and hard.

My bedlington x was done at 6 months and he has a dreadful coat, very VERY soft (not the hard linty texture of a bedlington) and though I can strip it, t he first few times I had to be very careful or he would have ended up bald, there was mainly just undercoat, very little topcoat at all. Stripping has improved it though!

My Deerhound bitch was spayed at just over 2, after her second season - her coat is certainly better than deerhounds I have seen who were spayed younger than this (b ut then, not many are) but it is still longer and softer than it was, and more prone to mats/tangles.