I have experimented several Enya engines with great results and I am sure the 45 6002 will work amazingly well too. I hope some one will post their experience with one.

I have no practical experience with the 45 6002.  It seems to me that the 4002 has larger internal fuel passage and maybe the port timings are a bit different, but still should be a very good for C/L. The 6002  head is interchangeable with the 6001, it has a  higher compression and as matter of fact I like to use the 6002 head with my 45 6001 engine.

If you tell me what plane your friend plans to use I can give you a starting point.

For a Pathfinder/Oriental Plus/RSM P=40k/DQ Master size model I suggest this venturi
https://cs206.xbit.jp/~w041133/store13/index.php?main_page=product_info&products_id=379

This NVA
https://cs206.xbit.jp/~w041133/store13/index.php?main_page=product_info&cPath=3_18&products_id=373

12x6 or 12x5 prop and 62' Lines

For a smaller plane you can use a smaller venturi like this one:
https://cs206.xbit.jp/~w041133/store13/index.php?main_page=product_info&cPath=3_19&products_id=378

with props like  11x6 11x5 or even a 10x6

good luck,

Martin

Post 3 _
http://www.rcuniverse.com/forum/glow-engines-114/535103-enya-45-6001-specs.html

I have followed the same ground. One very well respected Australian stunt flyer had his 6002 crank shaft internal bore sleeved down to the same diameter as the that in the 6001 and this made all the difference. I have tried it and can confirm that the engine is much improved. I cannot tell a great deal of difference between the two engines after the modification.
Another tip is to use an ST46 head. This makes the engine have that ST growl and probably performs like one too if I were a better pilot,  could perhaps tell!

Andrew.

Sleeving the crank bore,  can you explain how that is done, and what material is used for that.  
Also, what does that do that a smaller venturi would not also do ?
Do you know if the 6001 crank will work in the 6002 ?

Do you know if the 6001 crank will work in the 6002 ?

The short answer is NO .

The long answer is that there are too many differences which makes a straight swap impossible. For starters, the PCD of the retaining screws for the front housing is quite different. The 8 ball rear bearing of the 6001 fits the 12.7mm crankshaft with its 9.5mm bore while the 6002 uses a 10 ball bearing for the 15mm crankshaft and 11.4mm bore. The bore in the crankcase is different too. The 6001 is 28.5mm to suit the outer race which provides alignment while the 6002 is 29.9mm and uses a machined extension of the front housing to enclose the rear bearing and provide alignment. Apart from a minor difference in stroke (.2mm IIRC) the 6001 has a 6.3mm crankpin while the 6002 is 6mm so you'd need to swap rods. There are other minor differences such as the crankweb on the 6002 being 1.1mm larger than the 6001.