If you'll be learning with an instructor at the club, your kit built trainer should not be in much danger.
The PT-40 does not include: Fuel tank, wheels, wheel collars, spinner, or fuel tubing
The LT-40 does include those items
I've never built a Sig kit but most people really like them. I have built a GP PT-60 and I thought the kit quality was good. Either choice should serve you very well.
RCKen did an extremely thorough build thread
http://www.rcuniverse.com/forum/m_3439708/tm.htm on the LT-40 that you can use as an additional reference if you choose it.