Can LTSPICE compile BSIM4 models
According to LTspice's own help document (link to an outdated cached version; also pasted below), a LEVEL=14 MOSFET model is BSIM4.6.1.  According to the ngspice manual (Table 11.1; snipped below), it also uses 14 but can also use 54 as an alias.  If you are having trouble running a specific model in LTspice, change the LEVEL=54 in the model description to LEVEL=14.
There are seven monolithic MOSFET device models. The model parameter LEVEL specifies the model to be used. The default level is one.

level   model

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 1   Shichman-Hodges

 2   MOS2(see A. Vladimirescu and S. Liu, The Simulation of MOS Integrated Circuits Using SPICE2, ERL Memo No. M80/7, Electronics Research Laboratory University of California, Berkeley, October 1980)

 3   MOS3, a semi-empirical model(see reference for level 2)

 4   BSIM (see B. J. Sheu, D. L. Scharfetter, and P. K. Ko, SPICE2 Implementation of BSIM. ERL Memo No. ERL M85/42, Electronics Research Laboratory University of California, Berkeley, May 1985)

 5   BSIM2 (see Min-Chie Jeng, Design and Modeling of Deep-Submicrometer MOSFETs ERL Memo Nos. ERL M90/90, Electronics Research Laboratory University of California, Berkeley, October 1990)

 6   MOS6 (see T. Sakurai and A. R. Newton, A Simple MOSFET Model for Circuit Analysis and its application to CMOS gate delay analysis and series-connected MOSFET Structure, ERL Memo No. ERL M90/19, Electronics Research Laboratory, University of California, Berkeley, March 1990)

 8   BSIM3v3.3.0 from University of California, Berkeley as of July 29, 2005

 9   BSIMSOI3.2 (Silicon on insulator) from the BSIM Research Group of the University of California, Berkeley, February 2004.

12   EKV 2.6 based on code from Ecole Polytechnique Federale de Lausanne. See http://legwww.epfl.ch/ekv and &quot;The EPFL-EKV MOSFET Model Equations for Simulation, Version 2.6&quot;, M. Bucher, C. Lallement, F. Theodoloz, C. Enz, F. Krummenacher, EPFL-DE-LEG, June 1997.

14   BSIM4.6.1 from the University of California, Berkeley BSIM Research Group, May 18, 2007.

73   HiSIMHV version 1.2 from the Hiroshima University and STARC