Depends on what your plans are...the more money you have the faster you can go that is all there is too it no matter if you have a 1g or 2g, i definetly love both, if i didnt have alot of money i would just go with a 1g with good exterior and dont add gauty ish to it and just start working on it on the weekends and before you know it you will a very fast 1g
Differences between the two as far as motor specific can be found anywhere on the web, just do a basic search, other than that mainly exterior like mentioned before