I was planning on doing green keys with the extended length bilsteins up front. If I end up not liking the ride and returning to stock height will the extended length Bilsteins still work?

I think your best bet is buy the usual bilsteins and just put a bushing to get the extended length. From what I understand the extended bilsteins don't have any longer stroke, they are just longer. So you will get the same effect buy using a bushing to extend the overall length plus you can always go back to stock.

I agree, I purchased the stock replacements and love them. I put the bushing on the front and the ride is 10 times better, and no front shock problems. The 5100 series do not directly bolt in.

Thanks,
What are you guys using for a bushing? Any pics of the install?

The truely best option IMO is a shock hoop on each side and a single 7100 series Bilstein per side. It's the route I'm taking when I add Bilstein's to the front.

It would of course require taking some measurements but that's not a big deal. It is a rebuildable/revalveable shock, and IMO that's huge. For one as long as you keep the stockers you'll NEVER have to buy shocks again as they are rebuildable (keep stockers to install when sending out the Bills for rebuild).
Bilstein shocks do have a great service record though and a rebuild isn't something that you'd have to get used to. I'd say maybe every 50,000 miles a rebuild would be ideal with more miles in between fine for most.

Also it's a revalveable shock. And based off things I know of about shocks because of the Solo car I'd probably have Bilstein make a copy of the valving of a stock replacement bilstein. And then soften the compression a little to reduce the harshness of the cranked T bars, and maybe a little more higher speed rebound to help handle that spring rate increase and prevent the pogo stick thing.

...From what I understand the extended bilsteins don't have any longer stroke, they are just longer...
The compression on the extended Bilsteins s almost identical to the OEM replacement Bilsteins but the stroke is longer.

Similar valving, but too long. If you TRULY needed the length of these shocks, then those that have them would hear their front a-arms crashing on the frame mounted mechanical stops. I do not want this to happen...

Kennedy can you please post the extended, collasped, and travel specs on the OEM replacement Bilsteins. I can't seem to find them.

Kenedy here are the specs to compare the OEM vs the extended Bilsteins. As you can see the shocks fully compressed are only .6" longer so bottoming out the shock is not a problem. The shocks fully extended are over 3" longer so topping out the shock is not an issue either. I would highly recommed the 5125 over the OEM's any day. Having all the facts makes a difference.

Bilstein 5125 BE5-6140-T5:
11.77" collasped
18.42" extended
366/240

Bilstein OEM BE5-6140-H0:
11.10" collasped
15.35" extended
380/119