Cyclocross - How could I lighten up the Motobecane Fantom CX?

My girlfriend just got a Motobecane Fantom CX. She seems to be pretty happy with it. She'll be doing her first race in a couple weeks. The Sora shifters don't seem TOO bad. The only thing is, it's kind of heavy in it's stock configuration..

I feel a little weird having a lighter bike than my girlfriend, so what could I do to help lighten it up without spending too much money? I'm guessing the fork? How big of a difference would a tubular wheelset make weight wise?

I've always wanted tubulars for myself, and this would be a good reason for me to finally spend some money on a set. We could share them on race days.. :) But I'm not sure if there's that much of a weight difference from clinchers to tubulars?

Here's the bike she got..

http://www.bikesdirect.com/products/motobecane/images/fantomcx_gray_600.jpg

Don't sink any more money into your unhealthy relationship.

Fork and wheels- don't have to be tubulars necessarily to b lighter.

Clipless pedals, lose the outer chainring and front derailleur

Don't sink any more money into your unhealthy relationship.

Agreed. The bike is a really nice starter ride. Upgrading the fork and wheels is going to be expensive. You could have bought a better version to start and saved money doing it. IMO, just leave it as is and have your GF race it stock. Unless she's in the top 5% she isn't going to notice much difference in her times with a lighter bike. If she is in the top 5% why did she buy that bike?

Buy lighter tires.

It really depends on your budget.

Some nice used CF tubular wheels will make the most difference. Look to Ebay i've seen sets go in the $400 range with tires, but mostlikely your looking at $500 for some wheels and anther $100 in tires.
A new fork coudl shave some weight, but make sure that the rake and crown length match up.
That seatpost is a brick so for less than $100 you could drop about 100g

Not recommended to get a carbon seat post if racing cross.