As you may have seen in my new maple/old maple post i am trying to match the old wood flooring in my living room with new grade 2 maple flooring in the adjoining dining room and hallway. I am going to have to go with a dark color, it's jsut a question as to how dark. The old floor is a bit darker than the new floor. I am not even sure what kind of wood the old floor is...i have been told pecan, maple, etc.
If i put a stain conditioner on first will it help with the stain as far as limiting blotching, etc?

I would use an oil-based sealer on the bare old and new wood. Then use an oil-based finish that has been tinted with stain on the new wood only to tone down the lighter wood, it may take two coats of tinted finish. Always do some samples on some spare boards or on the floor across the new wood and the old wood in a small area and not the whole floor until you get the color right.
So after the sealer I would put two coats of untinted finish on the old maple and two coats of the tinted finish on the new wood, then top coat the entire floor with untinted finish. This system works good on maple and any other wood that is known for having problems with stain.
Buddy

and you recommend this for any color stain i decide to go with or just in the case ofthe mahogony?

SO, to paraphrase:

old wood: oil based sealer, 2 coats untinted finish, top coat of untinted finish.

new wood: oil based sealer, 2 coats tinted finish, top coat of untinted finish

You can use any color or colors of stain required to get the color you need.
As Pig-Pen said, this is a hard task but it can be done and your floor will look great. You may want a pro to do this.
We use Dura Seal poly satin and Dura Seal stain for tinting. We use the original stain and not the new Fast Dry wood stain.
We have had many years of success with this system.
Buddy

Sounds like a plan. I think the guy who is doing my floors uses the Dura Seal brand.
One more ? about the oil-based sealer you recommend going on first. Is this the same as a Stain Conditioner? I mentioned the idea of a stain conditioner to my guy and he said he could put a neutral base on first, which would have the same effect.
Also, is the final, "untinted finish" coat the poly coat?

The sealer we use for our oil and waterbased finish is Bona DriFast Sealer. It is not the same as the stain conditioner. I have used Minwax Stain Conditioner when staining the whole floor and it worked good on some jobs but did not work well on some antique heart pine jobs.
Do a test with the conditioner and see how it works, it may look good.
Yes the final untinted finish is the poly coat, satin works best when adding the stain.
I think the neutral base your finisher mentioned would have the same effect as the conditioner, do a test area.
I better go now, I live in Biloxi, Mississippi on the waterfront and we are about to lose power and it usually stays off for about 10 days after a hurricane.
Buddy

thanks for all your help. I hope you make out ok.