My goodness you're full of bad information..
First things first. The Picco .27 he mentioned IS in fact a big block. A "mid-block" engine is one which has the displacement of a conventional sized "big-block" (.21-.30+) but is housed in a crankcase that is closer in size to a conventional .15 or .18 sized engine. The Picco Red-Dot IS a mid-block, the .27 is NOT. Secondly, the TRX 3.3 is a .20, NOT an .18.
The TRX 3.3 is a significant upgrade from the 2.5. The Picco .27 (being a big-block engine) will not fit in T-Maxx unless you do a big-block conversion which generally consists of a longer chassis.