the SR does clear the firewall, although the trans tunnel does need to be modified to suit the S13 gearbox. i'd recommend using an R32 RB20 box as the overall length is shorter giving you a better shifter position. I have also mounted a CA18DEt in the engine bay, the firewall did not need any modifications, and the trans tunnel didn't need modifying either, the CA bellhousing is smaller in diameter.
the engine mounts are the rubber bushes, factory SR metal mounts are to be used with this cross member.
crossmember may be sold, waiting for a response. Place an offer, as the customer has offered below asking price