Sorry, didn't know how else to word it! I need a little help, I have had my mare about a month now. We had a few hiccups with her feet when she got here (shoer cut her front feet way too short and her shoes were too small) so I have been taking it easy on her. I ended up pulling her front shoes less than a week after she arrived, then eventually had her reset with thicker shoes to get her off the ground. She is doing a lot better now, is sound and moving out, and is comfortable. 

She is a finished 2/3D horse, BUT she has a LOT of go. She is getting a little better and is calming down a little, but her head goes sky high when she trots/lopes. Her back gets hollowed out and she gets very forward moving and bouncy, especially in her lope. I can get her to get her head down and flex at her poll and collect, but she still lopes like she is ready to run and she drives really hard. 

A part of me wants to stick her in a snaffle and bit her up to teach her to round out and relax a bit. Maybe some draw reins when I'm on her, again to teach her to collect and use her body. 

The other part of me is a little unsure because this is the first finished horse I have ever bought (I have always trained my own) and I just don't want to take away her ability to run? If that makes sense? I just want don't to undo what she already knows.  Is this something I just need to accept and not mess with her, or will teaching her to slow down, collect and use her body mess with her pattern? The previous owners used a tie down on her and she does not like the tie down at all, she shakes her head real bad to get away from it and she really doesn't need it, because she listens great without it. Oh, she also is a smoking pole horse.. as I found out today! Any advice will help!! I feel so unsure!

I think that almost *every* horse benefits from slow work and bringing them back down to slower speeds to correct issues. Harping on them and getting in a fight with them no, but slowing them down to remind them of the basics yes. There are pictures of Sherry Cervi at the NFR on Stingray in split reins doing slow work to keep her supple and listening to Sherry's cues. If that isn't a finished horse, I don't know what is. Yes there are some people who advertise their horses as never needing slow work, just take them to the rodeo and go, but I feel that leaves a lot of room for error. We rely on practice and muscle memory to improve, and if that's something you think will help this horse, then she might very well benefit from it. If she's as finished as you say, I wouldn't think doing some slow work would "slow her down" in any way. If anything, it would sharpen her skills and remind her of how to properly do her job, which would increase her speed versus making mistakes/tossing her head/etc. that would ultimately slow her down.

I dont think teaching a horse to travel well, be soft in the face and elevate thier back and really drive from behind is undoing anything. Youd be fixing a hole and could very well turn that 2/3D horse into a 1/2D horse once shes built up strength from working in proper collection.

Just my thoughts anyway...

I agree with the 2 posters above. Just like us, horses never stop learning... shes your horse, put your touches on her so she travels the way you like. I bought a finished head horse, that guy had me so scared to do anything different on that horse ... he told me to never EVER no matter what let that horse lope on his right lead .. I could go to the right but horse needed to stay on the left lead... I finally decided I had enough of that.. that horse now does flying lead changes like a champ lol!! Hes no worse off in the roping pen for it. Kind of a different scenario but you get my drift...I didnt ruin him by tweaking him to my liking 

I'd correct her, before those habits catch up with her. Also you dont know what you may have when you get her working correctly, may be better than what you started with. 

Yes, you're fixing the fundamentals she's missing.  I've bought a few horses over the years that were "finished" and running but that I thought could be better.  Purchased them, fixed the fundamentals they were missing, and suddenly they are clocking better and faster. 

Thank you all for your responses! I have decided to give it a go and work on it. Started yesterday.. she was not happy needing to slow down and collect, but I'm sure she will figure it out! Thanks again!