I would go with the DFV's new, because PSI will custom valve them for you for the springs you plan to put on them - for 24-2500 shipped. The AST's have next to no compression off the shelf, but would be good to pick up used to custom valve. The low speed compression that the DFV's have should outperform the rebound-reliant AST's. Besides, with the demand for DFV's, you are moreso renting them for a small fee should you not like them. Not the case with the AST's. You'll lose 1,000 bucks at least cole time to resale

 

I would go with the DFV's new, because PSI will custom valve them for you for the springs you plan to put on them - for 24-2500 shipped. The AST's have next to no compression off the shelf, but would be good to pick up used to custom valve. The low speed compression that the DFV's have should outperform the rebound-reliant AST's. Besides, with the demand for DFV's, you are moreso renting them for a small fee should you not like them. Not the case with the AST's. You'll lose 1,000 bucks at least cole time to resale. But again, if you can find some used AST's, snag them for cheap and custom valve them with nice and high compression knee.

 

I have the AST 4150's. I know someone who sold used, stock ones for very close to what he paid for them, so I would not use that as your purchase basis.

I will however, confirm that the 4150 is softer than even the 4100. It's likely you will eventually need to revalve them, to be competitive. I ran mine for a year of HPDE, and one TT event. They were fine for that, however, as i got faster, I ran out of adjustment at the upper end. So, I revalved in the off season.

You should consider this cost as part of your purchase. Once revalved, mine have been great.

 

Very good points, thank you everyone! As of now I'm leaning more towards the ohlins but still thinking. Are there any other brands I should be considering?

 

All the shocks mentioned in this thread can easily come with individual dyno sheets, if purchased from a reputable shop.

 

FWIW, my Koni 8242 adjust low speed bump, around 2-3 in/sec.

 

Have you considered Bilstein? The PSS (non-adjustable) can be custom-valved to your liking.

 

By the time he has put top hats and springs on custom valved PSS shocks he would be in the price range of these other combos. That is about $1000-1200 less than Penske 7500DAs, $1700 less the JRZ Pros. The key is when you start making modifications, there are options that would have been better.