I'm not sure I know of any SLSA that are certifiable for instrument flight. It is even dangerous to assume you can convert an SLSA to an ELSA and have it OK for instrument flight. It's all in the Operating Limitations and they have been revised so that it's likely the DAR who changes your certification from SLSA to ELSA will invoke a paragraph that says if the plane was ever restricted from instrument flight it still is. FAA Order 8130.2j. This discusses Operating Limitations for experimental airplanes. I'm no legal expert so interpret this and use it at your own risk.
"This aircraft may only be operated per the manufacturer’s aircraft operating instructions (AOI), including any requirement for necessary operating equipment specified in the aircraft’s equipment list. Night flight and instrument flight rules (IFR) operations are authorized if allowed by the AOI and if the instruments specified in § 91.205 are installed, operational, and maintained per the applicable requirements of part 91. (6)"
Some older ELSA are legal for instrument flight (mine is one) and I know of one SLSA that sneaked under the fence and is fully legal for instrument flight.
When you say SLSA's cover your price point, you're talking up to $200,000. If you have a lower number in mind it would be good to mention it. Good used SLSA can be had for $60,000, but like all other airplanes will likely have steam gauges.
It's pretty simple and not that expensive to get training in maintaining an SLSA or ELSA and the Rotax engine. You say you are not mechanically inclined. You'll have to decide how you fit that. I'd suggest Rainbow Aviation for the 16 hour or 120 hour course and Leading Edge Airfoils for the engine training, but that is based on my personal experience. You may have attractive alternatives for the engine training. That is by far the easiest way to avoid the problem of finding a competent A&P who is willing to work on your aircraft. Keep in mind that some A&Ps are not knowledgeable about the Rotax, but most are knowledgeable about the airframe side, and I've found plenty who are willing to help with airframe issues when they know I can legally sign off the condition inspection because of my training. I had an expert help me with some fiberglass work when I modified a cowling.
Many SLSAs have a long parts pipeline that goes back to Europe and takes time and money. SLSA required the manufacturer to give you a Letter of Authorization if you make significant changes to the airplane, such as swap a King radio for a Dynon or Garmin. Or change from tire sizes. Or install a new panel that is not on their approved list. ELSA avoids that unless you make a major change, in which case you have to get another Operating Limitation. People have varying experiences in this issue.
A Vans aircraft has the benefit of a tremendous owner user based and excellent support from what I hear. VansAirForce is the unofficial forum. Rans Sport Planes is good - I'm building a Rans S7 and friends have built Rans S20s. After market support of kit built comes from both the company and the model community.
I'd say the upkeep on a Rotax is much less than of a typical Lycoming. I've spent very little money on my Rotax. On the other hand, you will find some people less than enamored with Rotax after-sale support. In my opinion, it is a good engine so this only matters if it happens to you. I just bought a new Rotax bare for my second plane (building) for under $18,000 but you'll probably spend $20k to get the extras and because of the recent price rise.
There are a number of forums that speak to the Rotax topic. Like anything else, there are some people out there who don't know all of what they are talking about. They may be very good on some Rotax things and you can let that lead you astray when they talk about others. Take one or two Rotax engine courses from an official training source is your best start to avoid this problem.
You can buy an inexpensive standard certificated airplane like a Cub, Tri-Pacer, C172, etc., but you can also spend a lot of money bringing it up to good condition with good avionics. Nevertheless, my BIL sold his Tri-Pacer, which I flew and it was in perfect shape and flew, well, like a Champ
)) for $25,000.