A lot of people, myself included, have put an Apex seat on the RX-1. At your height, do not do it. The seat will be too short for you.
Also, the exhaust donuts can be a real hassle if you strip out the allen head bolts on the exhaust pipes. Instead of the stock donuts, try to find the copper ones which should last a lifetime.
And with the weight of that sled, you really want reverse.