Hey FF, So Wes and I picked up a TERO last week from Eric down in Texas - thanks Eric! We'd been looking at the TERO for some time, but didn't have the cycles to give it the time we felt it would need. Our unit arrived on Friday and we immediately got to unpacking and seeing what we had to work with. Wes, my pilot, is a nationally ranked RC racer at 1/8th and 1/10th scale, so he knows his way around RC cars. The HPI Baja frame has a long history and well reputed, so we were keen to see what we had to work with. First stop - the Castle ESC - had to go. It's an *older* design and prone to failure. In our quick tests with the stock unit, we also noticed a lot of whining, jumpy starts and *confused* forward / backward starts. Ugh. Castle came off and thanks to our friends over at HobbyWing, they provided us with a terrific 1/5th scale ESC to test - their EzRun Max 5 - it's their newest ESC and they were keen to hear our thoughts. One word - WOW! We had to drill out some larger holes on the mount plate, but other than that, it was a pretty simple replacement. Results are fantastic - if you only do one mod, this is the one! Our next replacement - the HPI servo needed to come out. It was very *soft* - wandered slightly at higher speeds and struggled to zero itself for straight runs. In its place - HiTec HS-5765MH - included with the Baja is an adapter plate for mounting this servo - it's a bit narrower than the stock HPI. Next on the list - receiver. Not a critical mod, but we prefer Futaba radios and went with the 4PKs radio and the R614FF-E receiver. We then took a good look at the shocks - they typically leak on receipt of the units. The gaskets just aren't sized correctly to form a good seal - both tops and bottoms. We thought about shopping around for the right sized gaskets, but in the end, Teflon is your friend and that worked well. Sealed each gasket. Also poured out the stock oil and replaced it with Team Associated oil. 42.5wt front on the HPI 2 hole pistons and 37.5wt rear 3 hole HPI pistons. We set them for "dead," or zero rebound. Nice. Last stop - power. We settled on SMC Racing 4S 6700mAh batteries in series for 8S total. We are very happy with all the modifications. Let us know if you have any questions!