Is Baker the way to go, then, or is there something else to consider?
If you're certain you've decided to make the change there are lesser expensive kits you'll find if you look. Personally I'd not recommend them. In the admittedly small sample size I've seen them used I've seen a failure rate higher than I'm comfortable with. The HD 6 speed kits are another option as are the Baker kits. Either have offered gear kits or complete transmissions.
Having installed both in 04 and 05 SEEGs my first question would be why you're considering this? The gearing on these bikes actually matches up pretty well for highway speeds (unlike, for example, the early SERGs that left you noticeably and uncomfortably higher RPM at highway speed). If the engine on your 05 has been touched up such that its torque curve is higher and/or appreciably longer I could understand wanting to make the six speed change. Aside from that, however, the gearing matches the torque curve of the 103 pretty well right out of the box. And for Willie's sake don't buy in to any notion of fuel economy improvements or other ancillary reasons for spending all the money it'll take to put in a six speed. That equation will never work out in your favor and there is no (zero, nada, zilch) economic justification for making the change. It's solely to improve the ride-ability of the machine.
The other justification, of course, is separate from the bike or its ride-ability. There is always the "just because I want to, dammit." That one never makes any sense for the wallet but has its own justifications...
