this one is easy..I have had both and the GRP is far stronger, better built, and has more power then the vspec. Not to mention the build quality is far superior imo (not that the vspec is a bad mill..it is great, but not in the same league as the GRP). I am not sure what the deal is with flameouts...mine never did, nor has any of them at the tracks I run at (flame out). The GRP needs to be tuned with the LSN, then the HSN..the LSN is crucial...it likes to be a little leaner then some other engines....tune that first, then tune the HSN and you should be screaming with good smoke, 200 degree temps, and 10 minute runtimes (pretty easily I might add). If it is flameing out your LSN is likely too rich. Also, go to a GRP 4 plug...it opens the tuning window a bit and the temps seem to be a little lower