There's some truth on both sides. Timing belts are generally not as much of a hassle to replace on north/south (longitudinal) engines as they are on transverse/sideways (east-west) engines...that's because there's usually more room to get to and remove the timing-belt cover. On some transverse engines, though, Jill is correct...they can be a PITA, and require several hours of labor....especially if the water pump is replaced with it, which is standard practice on some engines. I've even heard of a few cases where the engine had to be loosened on its mounts and shifted some to reach the cover.

 

I was comparing them to a gm LS motor or a ford v8 or even the 2jz supra motors that can handle high hp numbers with out cracking open the block in terms of handling boost. The wrist pins are the week point in the 2uz motors and give out at around 400 hp from what I was reading. Also from what I was reading after 400 hp the 1uz and 3uz tend to blow up.

 

There have been more than a few Lexus 1uz's in the SC400's and GS400/430's here that have been Boosted with Turbo's and Super Chargers and NOS. I had a SC400 both 97 & 99 that ran a 150 shot of Nitrous with No problems. . They went to the street and the Track with some great times.

The one I had was flawless with the Motor on Zex Nitrous Kit. For the most part the Tranny was the weak spot for some, of course not designed to handle double the motor output. Mine had No problems with the Tranny either. Not sure which ones you saw has problems handling Boost, but no engine handles Boost good if not tuned right for it.

 

Same engine in my 1992 S300 with the 5 speed manual combo. Smooth is the best description of this motor, love that aspect of it. Also love the low to mid-range torque and how the power is really linear, it pulls hard at 3000rpm in 2nd, 3rd or 4th gear, yet it still pulls hard near redline from 5000 to 6200rpm or so. You can really lug this engine without feeling a damn thing, it just pulls at low RPM.

Still though, compared to anything built since 2005 or so with six cylinders, its pretty damn slow. I mean rowing your own gears is fun, but man I'm sick of this 18-20mpg fuel mileage with premium fuel, even keeping your foot out of it on the highway at 70mph nets you a best of 23, maybe 24mpg on premium. I still love my SC300, the styling is timeless, but the practically kind of sucks, along with the MPG's, especially considering premium fuel is now 50 to 90 cents more a gallon than regular.