Mountain Biking - Build up my carbon Rush frame!

So, I'm a roadie who just got a killer deal on a Rush carbon frame with the Fox RP23 rear shock as my very first mountain bike ever. It should be in this week and I'm eager to ride it but all I have lying around are road parts. I need to build it up and would like to ride it as soon as possible so I've come up with a few options:

1. Piece it together like I want it even though it may take several weeks of patiently aquiring the right components. Estimated cost: $God only knows (better?)

2. Buy an entry level hardtail like a Cannondale F9, switch over the components, dump the frame and gradually upgrade the parts. Estimated cost $300-400 now, more later

3. Buy a used bike off Craigslist (like a Kona Hoss), switch over the components, and get a good return on frame and extras. Estimated cost $700 now, recoup $300 selling extras, no near future upgrades needed

4. Trade the carbon frame for a friend's AL Rush 3. No cost, may make money by building up my frame for him :( (only considering because the last thing I want to do is trash a carbon frame the first time on the trails skidding out into a tree)

5. You tell me. . .

Any input is greatly appreciated

FWIW I'm a Cat 4 road racer and plan on racing mountain bikes next season too.

Do you want light? Cause that will cost way more than $500 to build up a frame.

Yeah, I'd probably spend that much on a lefty, but between friends with discarded components after upgrades and my shop discount (hee hee) I don't think it would be more than $700 for a usable build.

huh?

Whats the point of building a frankenbike with a carbon rush. Any benefit the carbon frame had over the aluminum one (1/2 lb, bling) will surely be wasted with a bunch of crudy parts.

Just get a rockhopper or something, its not likely a cat 4 road racer will need anything more than that anyway.

OK, so you're voting against the frankenbike option, that's cool.

My friends' components are not crap, just a step or two below carbon bling so the only frankenbike option is #2 with an entry-level hardtail switch-over.

The frame is shipped and on it's way. Done deal. You're probably right about what I need, but since when do cyclists get what they need?

I wouldn't get a Rockhopper anyway because we don't carry Specialized.

If you're serious about getting into the sport, you might as well commit more money into the bike. If you aren't, then you should just sell the frame and get an entry level Cannondale.

Fine.

Look, the point is after spending as much as I have on this frame and a new road racing frame (brooks saddle/bartape/king headset for my commuter) I don't have a whole lot left to play with THIS MONTH.

Given my buying habits, MUCH will be spent to make this a nice bike EVENTUALLY. the problem is I want to ride now (insert whine)

I disagree with the previous posts. There is nothing wrong with building up this frame with decent but not fantastic parts. It's what I'd reccomend anyways. If you get something like a Reba or even Recon fork, solid but not ultralight wheels, and X.7 or LX/SLX drivetrain (the mountain equivalents to 105) you will have a pretty nice, but not fancy (except for the frame) racing/trail bike.

As you ride more, you will develop a preference for component choices that you can't really know now. Do you prize durability and traction? Want a hardtail? Never use the big or little ring? Only time will tell. If you fall in love with the bike you can transfer the mid-range parts to a hardtail and bling that frame way out.

also the lefty id a great fork but apparently re4quires a lot of maintenance according to a local elite racer I know

Fox makes some beautiful suspension

personally I'd choose great suspension and mid level parts starting out

I disagree with the previous posts. There is nothing wrong with building up this frame with decent but not fantastic parts. It's what I'd reccomend anyways. If you get something like a Reba or even Recon fork, solid but not ultralight wheels, and X.7 or LX/SLX drivetrain (the mountain equivalents to 105) you will have a pretty nice, but not fancy (except for the frame) racing/trail bike.

As you ride more, you will develop a preference for component choices that you can't really know now. Do you prize durability and traction? Want a hardtail? Never use the big or little ring? Only time will tell. If you fall in love with the bike you can transfer the mid-range parts to a hardtail and bling that frame way out.

Nicely put. I agree.

If all you want to do is ride it ASAP, then I would opt for a build kit from pricepoint or Jenson.

Then all you'd really have to upgrade later is the wheels, if you want go fast xc racing wheels.

If you want to ride ASAP how about renting a bike to hold you over and taking your time with the parts? You'll have the parts forever (pretty much) so why get stuff you don't want in the name of getting on the trail fast? Just get on the trail with another bike and take your time on the parts.

That's essentially what I want to do, but without the 1k price tag.

Assuming all goes well, I may be aquiring a very slightly used Kona Hoss (frame too big) and switching over parts.

It's a overly beefy build for a Rush I know, and I know I will eventually upgrade parts to make it lighter and reflect my (eventual) riding style. Plus I have lefty lust.

Thanks for the input

Update:

Frame came in! Everyone at the shop was drooling over the black and blue beauty. Ahh, just the thought of it.

So to build it up:

Yesterday I bought a barely used (I know because I sold it to him from the shop I work at and it still had the feel of bike lust on the frame) Kona Hoss Deluxe. Unfortunately, as I took the Rush out of the box I remembered two key points: 1.5 headset and BB30. Really? How did I overlook that?!

The adapters would have to be ordered and I am not liking the prospect of payig another couple of hundred for a temporary fix.

The saga continues. Turns out the 18" Hoss frame actually fits my freakishly long torso and still gives me a little inseam clearance (5'7", inseam~30" with shoes) So I'm going to learn how to ride on an indestructable kick-butt hardtail and gradually build-up my carbon bike to race next season (do I hear a carbon lefty, whoop, whoop)

Thanks for the help!

Sound slike a good plan. The Hoss will make a great beat around/bad weather bike for a long time to come.