t-5 confused which one?

[Flat Ernie]

The positive stops are typically bolts for the forward/backward. It does prevent moving the shifter a certain amount. It is not stiffer springs.

Here's a 'factory' Hurst unit. I think these were used on some of the early SVO and Cobras. Hurst offered them for a while too and then changed the design. This should give you an idea of the concept:

http://www.ebay.com/itm/5-0-Mustang-...r#ht_558wt_932

Here's a standard $50 shifter. The stops are not installed in the picture, but the hardware packet has the bolts:

http://www.ebay.com/itm/83-04-FORD-M...ht_3141wt_1018

Here's what that $50 shifter will look like with the bolts installed (this is a more expensive shifter):

http://www.ebay.com/itm/E-HP-Mustang...#ht_4491wt_821

And here's the $30 shifter:

http://www.ebay.com/itm/01-02-03-FOR...ht_2994wt_1160

Same thing as the $50 shifter.