RE: Savage 5.9 or GST 7.7?
To be honest I don't have one, however my bashing buddy has the Genesis and Nemesis and has put his trucks through more paces then 90% of the people who buy one. He is the most knowledgable CEN person I know and I value his opinion.
First off, the 7.7 is the hardest motor hands down to break in. I pulled that pull start with reasonable temps in the 40's plus and it is a bear even after break in. The bottom line is that just to get the trucks running consistently and without breakingtakes some serious cash. He refuses to sell them because the amount of money he had to dump into both rigs plus the amount of time invested in maintaining them wouldn't be worth any price tag to him. He told me flat out that they are difficult to tune and a waste of money. That isn't hardline, it is the truth.
Do they have a ton of redeeming value/bashability/great parts/engineering built in? Can they take a punishment? You bet! But compared to the parts availability and "bloodline" of the Savage XL and its predecesors it is a no brainer at least to me. You will easily invest a small fortune in these mammoths and to him (again a VERY knowledgable monster truck and truggy racer/basher/scratch builder I value his input.
My vote for best bang for the buck would be any savage, the LST2 or the XTM MMT. The MMT is by far superior to the CEN from a beating standpoint and for $450 RTR and by its sheer size I think you would be much happier. Plus XTM motors are much easier to run/tune/get parts for since the Mach/XTM/Dynamite/SPortwerks have many common threads.
Tha is my 2 cents...go for the savage or save $150 and get an RTR XTM...you won't be sorry. They both (XL/MMT) have lots of great features and value...I can't make that decision for you unless I knew more about you were looking to do with them.
Good luck!