javaws and plugin benchmarks (from startup2 refworkload benchmark) run with fx1.3b111(promoted build b07)
and jdk6u18b03 in "warm" mode (deployed cache is kept untouched)  show from 10% to 20% regression 
comparing to previous jdk6u18b01. 

10% - 20% is about 100ms in average.

Here is the detailed comparison:

==============================================================================
6u18b01_fx1.3b07:
  Benchmark           Samples        Mean     Stdev             Geomean Weight
  app_animpath_jws         20      907.70     25.68            
  app_fx_jws               20      511.60     30.03            
  app_jmc_jws              20      724.15     10.52            
  app_mediacenter_jws      20     1754.60     35.86            
  app_swing_jws            20      547.60     14.68            
  applet_animpath_jpi      20     1087.40     15.68            
  applet_fx_jpi            20      722.00     32.91            
  applet_jmc_jpi           20     1099.10     56.67            
  applet_mediacenter_      20     1978.85     16.25            
  applet_swing_jpi         20      705.45     11.57            
==============================================================================
6u18b03_fx1.3b07
  Benchmark           Samples        Mean     Stdev   %Diff     P  Significant
  app_animpath_jws         20      915.55     38.05   -0.86 0.450            *
  app_fx_jws               20      615.55     10.64  -20.32 0.000          Yes
  app_jmc_jws              20      801.40     21.65  -10.67 0.000          Yes
  app_mediacenter_jws      20     1851.50     33.02   -5.52 0.000          Yes
  app_swing_jws            20      614.75      9.13  -12.26 0.000          Yes  
  applet_animpath_jpi      20     1147.60     47.09   -5.54 0.000          Yes  
  applet_fx_jpi            20      790.60     12.75   -9.50 0.000          Yes  
  applet_jmc_jpi           20      997.65     12.63    9.23 0.000          Yes  
  applet_mediacenter_      20     2030.55     12.86   -2.61 0.000          Yes
  applet_swing_jpi         20      794.65     12.82  -12.64 0.000          Yes
==============================================================================


The regression is observed in all benchmarks except applet_jmc_jpi and app_animpath_jws.
applet_jmc_jpi actually shows stable improvements.
app_animpath_jws looks like fluctuate too much, so hard to compare.

Please see also results here:
 http://spb-phare.russia.sun.com/compare?ids=16541,16581


I also tried to reproduce the regression using 2 simple benchmarks app_swing_jws and app_swing_jws
and the regression is easy reproduced:

==============================================================================
./6u18b01/results/:  Benchmark           Samples        Mean     Stdev             Geomean Weight
  startup2                 10      623.68     23.33            
    app_swing_jws          10      556.30     42.39             0.50      
    applet_swing_jpi       10      700.10      9.70             0.50      
==============================================================================
./6u18b03/results/:
  Benchmark           Samples        Mean     Stdev   %Diff     P  Significant
  startup2                 10      697.99     15.08  -11.92 0.000          Yes
    app_swing_jws          10      614.20      7.47  -10.41 0.002          Yes
    applet_swing_jpi       10      793.60     35.01  -13.36 0.000          Yes
==============================================================================


The similar regressions are observed in "coldapp" mode (application jars are purged from deployment cache) as well:
 http://spb-phare.russia.sun.com/compare?ids=16555,16584