realskiers

well first to be a good/great decender on hardtail especially a 26 inch XC angle hardtail require kung fu skill level. Most people do not have it, and those that do have it usually do not ride 26 inch XC angle hardtails. the easiest way to go faster DH is to get a full suspension trail bike.

The next easiest way is to get wide sticky low pressure tubeless rubber.

some other things that help, brakes that allow ONE FINGER braking. bars set at the right height and with enough width. different for everyone but so many people still run bars that are much to narrow on a stem much to long IMO.

on the fork.

I have run 100mm fork on bikes not designed for them for quite a while, I just ran them sagged a ton giving me a more complaint ride with out messing with the geo to much. Honestly is seems like your wife could beneift from a higher front end.

I would not mess around with a QR fork at all if buying a new one.

I have used Fox, Rock Shox, and marzochi.

Fox IMO have had the worst feel out of the box, with the exception of 34 and 36. They are no user friendly during service and have bad taste in my mouth after my 1 year old Float 32 RL killed its seals, got bushing scores on the stanchions and now needs a ton more part than I really want to put into it. I will say this if you get one, get it and put lighter weight oil in it since your wife will be to light for the stock oil. admittly I never did any maintence to that damn thing but I have also ran rockshox for years with out touching even the oil and they never did that to me. fox is pretty easy to deal with. If I had a bike that came with a 34 or 36 though I would probably keep it and just make sure I take better care of it.

Rock shox has by the easiest fork to work on, and with that said they never need worked on for the most part. the reba/sid are both great complaint and plush fork while pedaling great. The RLT is a nice damperner but the RCT3 is amazing. You can probably get a close out dual air fork for pretty cheap. easiest company to deal with the bike business IMO.

Marz - easily the best feeling forks I have ridden might not pedal as well as the rockshox but going down they feel great. can be hard to find, and the company has had issue in recent years leading to customer service problems.