I need some advice on a mountain bike purchase. I went to my LBS and told them I was looking for a mid level hardtail 29er to get into off road races and tris. They suggested the Trek Mamba. Rode it in the lot and it felt great and right what I was looking to spend. Then the guy pulled out a Trek X-caliber and said this was a “demo” bike. The story was that some big wigs from Trek showed up at the store and took that out riding once so it was marked down quite a bit (but still slightly more than I was looking to spend. 200 more than the Mamba). I guess I’m looking for the biggest return on investment with this. If I spend a little more now will I need to spend less later on replacing broken parts? I’m a grad student so money definitely IS a concern. Thanks.