I don't think this is mentioned anywhere in the RAW, but is there a way to upgrade or replace cyberware/bioware? Suppose a character that started with muscle toner rating 2 wants to upgrade it to rating 3, can it be done? How about replacing those wired reflexes with synaptic boosters (since the description of each specifically states they don't stack)? Is it possible? Would there be some kind of trade-in discount (subject to the trustworthiness of the doctor and the whims of the GM I'm sure)?

I know a secure network can be setup using a skinlink, but would a separate skinlink have to be installed into every device you wanted on that network, or just one for the commlink? I'd say yes, on is needed for every device, but what do the denizens of Dumpshock say?

Back to cyberware: suppose I want both my commlink and a sim module implanted so I constantly have access to them. Could I save on essence costs by putting a standard sim module into my commlink and having just that implanted, or is that not kosher?

And last but not least; could anyone provide more detail on the GMC Everglade? What kind of hovercraft is it? What does it look like? How many passengers/ ho much cargo can it hold? Is it a Star Wars landspeeder style hovercraft, or is it more like modern day hovercrafts that ride on a literal cushion?

In previous editions, cyberwear you removed left an 'essence hole' that you could later fill up with other wear. Example: You start with wired 1 (2 essence) you get them yanked out and upgrade to wired 2 (3 essence), you total essence loss is only 3, not 5. If you just had your wired 1 yanked out, you would still only have essence 4 though. It's just that you could get up to 2 essence of wear without any more essence loss.

AFAIK, all devices need the skinlink modification.

As for the Everglade, I'd assume its a rigid-sidewall air cushion hovercraft and not a Starwars land speeder.

As repulsor-lift technology doesn't exist in the SR world, you are looking at a traditional air-cushioned hovercraft - I wouldnt' expect too much maneuvering control out of something that's fan powered...

Some bio-ware can't be upgraded, as it's a vat-cell enhancement and harder to remove once the graft fully takes.
There is a mention in the book about upgrading cyber if I recall, don't have the BBB with me right now, so I'll get back to you in a couple of hours when I get home.

I'd assume that most bioware can be 'upgraded' but alot of it would be very hard to remove. You could go from cerebral booster 1 to 2, but removing your cerebral booster might be more mokeying around with your brain that most surgeons would want to do.

Implanted commlinks come with Sim Modules standard (and included in the price and Essence loss).

As for the Everglade, I'd assume it has an air cushion, and maneuvers through the use of vectored thrust.

Vectored Thurst and Hovercraft are not the same thing, don't confuse tech.

I know. But you don't need the full T-bird treatment to have a small vectored jet engine on the back for steering and motive power, rather than the bigass fan-with-air-rudder setup modern ones have.

Nick's got a point there. A hovercraft with a vectored-thrust maneuvering system would be a lot more agile than your basic fan-and-vanes arrangement.

the thing that is most confusing with SR4, is what happens if i remove my alphaware wired reflexes and replace them with synapic acelerators? this can very easily change which of cyberware and bioware is higher essence cost- you could downgrade to a lower reaction and end up losing essence.

if you have 2.5 essence of bioware and alpha wired 2 (2.4 essence), then thats 3.7 essence overall. but if you also have .2 essence of other cyberware, such as a datajack, then you go from (2.6+[2.5/2]) to (.1+2.5). that leaves an essence hole of 1.25, from removing 2.4 essence of ware. so upgrading to synaptic 3 in this case costs an additional .25 essence more than the wired, even though the total cost was .9 essence less. the exact value is going to be very dependant on the balance between cyber and bioware.

Assuming you run with the "Essence Hole" rule, I would think the best way to deal with "filling the hole" and the confusion resulting from the cyber/bio conversion is to say that a cyber essence hole can only be filled with cyber, and a bio essence hole can only be filled with bioware. This makes a fair amount of sense (I think), means you can keep the calculations simple by simply attaching the essence hole to your cyber or bio essence loss tally, instead of attaching the essence hole to your modified essence value.

Sorry if my phrasing comes off confusing and weird. I assure you the logic is sound in my head.

Separate "cyber/bio holes" vs. just one "essence hole"
Just off the top of my head:
1) cyber/bio is slightly more "realistic", or sensible, as Eryk put it.
2) cyber/bio is slightly more complicated to track.
3) cyber/bio is slightly less advantages to PCs in certain situations
YMMV, but until the FAQ or book comes out to clear it up, just pick one.
Am I missing any pro's/con's?

It is probably the most fun not to track which type of ware created the hole. Most chars will start out with heavy cyber/less bioware due to monetary costs, and want to switch to bio when the cash flow starts (like this is ever going to happen ).