Are ARC new amps much better than older models?

I am in the market looking for an amp to match my Von Schweikert 4.5's. I have been looking on this site at the many models available afrom ARC. I just saw that The Absolute Sound gives their current lower end model product of the year in the amplifier category. As a recovering vintage audio addict, it really is hard to believe that the new ARC products are that much superior to their older products. I realize that they must have new wrinkles to sell their new products, but are they really that much better? I used to think that the SP 10 was about as good as it gets in preamps. Have they really exceeded it? How about their amps from 5 or 10 or even 20 years ago. I know that parts have gotten better but when Western Electric transformers are still the standard, couldn't one just update an older ARC amp with the newest high resolution parts available. Even ARC will update their SP 3 for about $1000.00 to meet current specification preamps. I must admit that I am very jaded about the high end. This is why I started my new system with the 5 year old Von Scweikerts. I am sure the latest generation 4's are better in some ways, but today paying $2000.00 for this much sound quality seemed a better bet than spending about $6,000 for some fractional percentage of improvement. Would this philosphy also work for the ARC amps?
I'm an SP10II owner - bought it new 20 years ago and have never been tempted to change it out. For me it has always had the correct tonal balance, a wonderful midrange which only falls short very slightly in resolution and the frequency extremes compared to todays product & the phono stage is still world class. Built like a tank and best of all, when I have a problem it gets solved promptly by ARC. The SP 8 is still highly sought after. Both of these pre amps have a different sonic signature than most stuff made today. If your looking for "highly resolved", equipment which has focused on finding the last bit of flyshit in the pepper (acoustically speaking), which usually comes with an invasion into tonallity, then look elseware. That said, I think some of the speakers made in the late 90's are much better than those made in the 70's and 80's. There really are some highly resolving speakers with neutral tonallity available at reasonable prices.
Newbee's not the only person out there who thinks highly of the older ARC models; I'm sure many of them will be chiming in. I agree with him--it seems that ARC chose the path over the years (and it's not just them--most manufacturers have been doing this as well) of trying to wring more and more detail out of the sources being fed their amps and preamps and make them more accurate in passing the signal that they are fed--hey, that's what they should be trying to do--which has led to a more analytical house sound than their earlier models. There have been improvements in parts over the years which have benefitted amp designers, but the basic circuits haven't changed all that much. An SP10/D150 combination might not be the last word in resolution or bass control, but it will get the midrange right, and I'll bet it would do a great job of conveying the music to you. I'm sure that they could be updated if you chose to go that route as well; ARC does a great job supporting their older products.
In general all of them are great no matter SS or tube.
The older models probably would need some service to be done with newer better parts.
The older D series ARC amps are increadible, simple and great sounding and will sound on the level of new ones if proper internal modifications will follow + you'll save money buying these models at low hundreds.
Loads of upgrades available through the manufacturer that can offer to you an excellent service and even customize the amplifier for you needs if possible or neccessary.
Another option is to have Steve Huntley from Great Northern Sound upgrade the older ARC equipment. I beleive he used to work for ARC so he knows the stuff quite well.

I had him upgrade my VT130SE & LS5-MKIII by changing the power supply, Caps and key components in the signal path. He also installed EIC power cord connectors.

I'm very pleased with his work.
I can't claim the same breadth of experience or knowledge of ARC products as some others on this site.I have owned and enjoyed a LS2B for nearly a year( must have been over a decade old before it descended on my rack!)when the familiar urge to upgrade and the need for a remote propelled me towards a SP16.I was't prepared for such a quantum leap in terms of soundstage and midrange improvement.The SP16 is barely 3 weeks old and presumably has a long way to go before being broken in.This is a superb preamp that would be very difficult to beat at this($2400) or a shade higher price band.
To answer your question regd.newer models of ARC, from my limited experience, the answer is a unqualified yes - they sound superb.
Happy listening.