I am fortunate to have both a Levo and a Rise. Both are great and both are extremely different rides. If you are fit, or your buddies ride in Trail while you are in Turbo you will be able to keep up on the Rise. The Rise is more "fun" to ride but the Levo is better in the chunky stuff.
Not with that specific saddle, but I have come across this with other Spesh & other Mfg saddles. Cleaning and greasing the saddle rails has usually fixed it for me. Sometimes it's the rail to saddle interface and I have not found a solution to that noise source.
I can feel the difference in weight, but it is not enough to really change my personal riding style. If you are a rider who is very active and pops off everything in sight, you will definitely notice the additional weight.
Get the Gen-3. You won't be sorry. I started with an SL and it was great, but going to the Full Levo upped the fun level and I can now keep up with others.
I'm almost 6'3" with longish legs and ride an XL. I can ride L's but feel like I am too big for them. The seat needs to be up so high the Handlebars are too low for my liking even with max spacers. Reach is not as much of a problem as stack height.