The answer to your first two questions is yes. I have both of these models and have chipped both of them. With regards to the HST I replaced the motor with a modern 5 pole ringfield motor and the front bogies were replaced with bogies that have pickups on all wheels. It runs like a dream. I also added small LEDS in the 37. However is it worth it? For a brand new HST you are looking at over 100 pounds, with superb detail, running ability and full lighting. The cost of my project was around the thirty pounds mark. My motors were purchased from Abbiegails plus I added seven coaches for around another 30 pounds. So for aboput 60 pounds I have a HST with great running, seven coaches for around fifty pounds less than a brand new power and dummy car.
High towards the far post,Howard with a header,Hes done it!Steve Howard has scored for Leicester City,Bedlam here at the Walkers Stadium. the Leeds United players are flat out on the turf in utter despair. Leicester City are going to win again
I agree with Sishades, well worth doing and will save you mega bucks on the cost of a brand new HST. The 37 is the easiest conversion and lighting LED's can be found at several sites. I use Vero board and 1.8mm White High efficency LED's for side lights and "Domino" lighting, Resistors suitable for 1.8mm HE LED's would be 10K 0.25W, The LED's can be supplied with current as low as 0.4ma and still give a decent light.
For headcodes I use standard 1.8mm Yellow LED's and 1K 0.5W resistors. Your loco has a solid plastic headcode with a sticker on, you would need to modify this by removing the plastic inside the headcode box, fitting a clear plastic window into where the headcode area was and refitting the headcode sticker and LED behind the window, the side lights will drill out nicely using a 0.5mm or 1mm drill bit, drill these out by hand. If you use a dremel etc don't power it up just turn the chuck by hand, as the increased friction from the bit being at high revs when powered up will cause melting damage to the plastic around the lights. Fitting a decoder to the class 37 is a very easy process as well, if you want details on how to fit the decoder corrrectly PM me.
When fitting clear poly plastic use Humbrol clearfix, it is a polymer resin glue that won't cloud the clear plastic if you happen to get any on it and it peels off easily by using a finger. If you use a normal poly adhesive you will get clouding of the glazing.
Have to say Sishades is spot on. I have done the same with the HST..ie re-motored to the 5 pole and extra pick ups on the leading bogie and what a transformation. A TCS decoder later and a great runner.
Having said all that, the new HST is the better model but as stated, you need well over 100 pounds to buy it then the rolling stock.
PM me Daz and I will take you through the class 37 conversion step by step, I have a scrap class 37 body I can use for the job and a 37 I can show you how to fit the decoder on. Glad to be able to help a fellow modeller.