[jons911]

Option A: This would probably run you around $2000 if I remember correctly from our host's engine rebuild wizard. If you haven't already, I would give that a look. (Warning, it is a bit lengthy)

Option B: As long as your cylinders are Nikasil, you would only need a new set of pistons to bump up the compression ratio. I've mostly heard people using J&E which would run you about $1100 I think, but there are a few other manufacturers (wossner and carillo?). Opinions differ, but you would probably be safe at 9.5:1 on pump gas and single plug, which gives you a whole point of CR over stock US spec. As for cams, I think those usually run around $1k, and each of the manufacturers can help you select the right cam for your use and engine setup. I read on hear a little while ago about a guy who had Dougherty make custom profile cams to give better mid range performance at the cost of slightly less top end power since that fit his driving style. I believe several other Pelicans have since purchased that cam grind. Finally, you definitely want to get a new chip that is programmed to accommodate all of the engine changes. Steve Wong seems to be the go to, however, since I have an SC, I can't comment either way on chips.

Option C: This is my personal favorite. First off, no, you should probably not run single plugs on 91 if you do this option. Like you said, you can go 98mm p&c's for a 3.4, or go 100mm p&c's for a 3.5.
-Since you already have the 3.2 95mm cylinders, building a 3.4 is a much cheaper option. You can have you cylinders sent to EBS who will bore them out and have them replated in Nikasil by Millenium Tech. I don't know the price on that, but I think it was around $600-700. From there add in a set of 98mm pistons at you desired CR and a matching cam.
-The 3.5 will be a lot more money because you will have to source the 100mm cylinders. If memory serves, the original Mahle cylinders don't have enough thickness at the base when they are bored to 100mm and are prone to failure. LN sells slip fit cylinders which means the case doesn't need to be bored to allow for bigger cylinders. However, those cost a pretty penny: $3740 for cylinders and $4780 for p&c set. Once you have a set of cylinders, the process is the same as the 3.4: pistons and cams to match. The pistons don't really change price for the different sizes, so it is mostly the cylinders that affect the price.
-Twin plugging: You will certainly want to consider twin plugging if you go for the big bore. I've heard of people running single plugs with a 98mm bore, and certainly the Max Moritz setup did, but those pistons also had a special dome design to help the burn front. For protection, most people tend to go twin plug. Plus, with twin plugging, you can run higher CR. The downside is that it will probably cost about $2k to twin plug. I won't detail the various setups for this, but I can find a few helpful threads for you if you want.

Also, upgrading your exhaust is another way to get a little bit more out of the engine. Debatable on whether the power bump is worth the money, but that's a personal decision.

Hope this helps at least a little.